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Hi,
I bought an orphaned 245 in April that had been in storage for a long time. It had a lot of problems, but I was able to drive it home and the cruise worked well on the trip.
I've been working on the car over the summer and it's now inspected and on the road but somehow the cruise didn't survive the make-over. I'm suspecting latero genesis. If I understand the term correctly it means I may have screwed it up by fixing other things.
I re-wired the tailgate, which was a mess, bypassing the hinge and replacing the grounds. I know the brake lights are part of the system, but all 3 are working well as does the rest of the back end.
I had the cluster out. The lens was cracked so I transferred everything into a new box, deleting the service reminder and jumping the temp fakir at the same time. The yellow wire has been firmly re-attached to the double spade. There are no codes showing. The speedo and odo are functioning.
I replaced the master cylinder after a lot of brake work and then monkeyed with the brake pedal switch, mistaking it for the brake light switch. I've reset it so that the wires show continuity with the pedal up and open when depressed. There is also continuity between the output wire and ground, and the switch passes the blow through test. That seems to be as it should.
While I was toying with the switch a 10 inch length of wiring harness fell out from around the steering column. Four wires, blue/yellow, white, green and red, dead ending at a female receptacle that looks like it would accept a relay. The colors don't correspond to the wiring diagram for the cruise, so it's probably irrelevant. The other end disappears into the monster harness behind the cluster.
I've come to the point in Bentley's troubleshooting where he says to make electrical tests on the components, hence some questions.
His diagram p. 360-15 shows a black ground from the control unit. Where might that end up ? I had the center dash apart so if it's in there I may have missed it.
Also, his diagram of the stalk switch shows 2 blue wires, a white and a blue/red. On mine one of the blue wires is a blue/ yellow. Maybe a typo. Is the blue he's showing at terminal 1 a power lead, and should I have 12 volts there ?
I haven't removed the stalk to check it, but I do have a clean fuse at #12 and power from it.
And thirdly, is there a way to jump the vacuum pump or test it ? I should mention that the vacuum lines all seem to be sound. The rubber is supple and without cracks. I've connected a hose to the servo, and there's movement at the gas pedal when I suck on it.
Any other ideas ? I have a 91 with an operating cruise and I can swap parts, but I'd rather leave that as a last resort.
Thanks, Peter
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On mine the stalk wires are blue, blue/red, blue/yellow and white.
Parts will interchange with the 91.
You can power the vacuum pump for testing.
I don't think there are any relays associated with the Cruise Control.
Dan
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The ground may go to the left side of the center console frame, there are several in that location
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Thanks Dan.
I'll have a look there as I did have that all apart. If I don't see anything I'll try and trace it from the Control Unit as Art suggests.
I'll make some time this week and let you know.
Peter
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Hi Peter,
I posted a reply but replied to Dan (below) about the grounding. Figured I'd better post directly to you as its scrolled off into last month's oblivion.
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Art Benstein near Baltimore
The early bird gets the worm, but the second mouse gets the cheese.
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Hi,
Sorry about the delay. Is anybody still there ?
I pulled the cluster today and didn't have any trouble getting to the wiring. Undoing the 2 screws under the steering column that hold the CCU lets the whole mess move forward.
The black wire is grounded, no bout adought it. The ground point looks to be on the left side of the column, just below the stalk. I get 0 ohms between the #8 pin and a set of 2 black wires connected together with both ends disconnected. There are 4 wires on 2 terminals at that point.
I took everything apart and it looks good, no corrosion, all clean and tight.
I should have checked for power at the box, only thought of it after closing, but there's power at the switch.
The switch seems to work in all 3 positions, probing the appropriate wires while turning it on and off.
I hooked my battery charger to the vacuum pump after disconnecting the wires. It pulled the gas pedal to the floor and the brake pedal released the vacuum as it should so I don't think the fault is with that system. The brake lights are working and I get 12 volts across the 2 pins at the brake switch.
That leaves the control box and the VSS. I have a hard time believing the CCU has failed by sitting in a warm, dry shop for a month, but things happen so I'll swap it out with my working 91.
Before I do, I'd like to take another look at the speedometer because I had it off the circuit board when I changed the cluster box.
I'm not sure that I'm understanding the wiring. The 93 diagram shows a connector where the blue/black from 6/31 splits to a blue/black going to the ECU, and a yellow wire to the CCU. Is that connector on the circuit board so that both 6/31 and the double spade are vehicle speed ? I'm not getting a 3-1-1 so it seems the ECU is getting a VSS. I haven't looked so I may be wrong, but I don't remember any wire at the double spade on my 91.
I guess my questions are...Does the yellow wire at the double spade go directly to the CCU and is there a test that would indicate that there is a VSS on that wire?
Any help or suggestions would be appreciated.
Peter
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Hi Peter,
I like your thorough approach. You came to the same conclusion I did regarding the ground location. I posted this elsewhere in this convoluted thread:
And an answer to the mystery relay socket -- DRLs for the Mapleleafers.
As for the yellow wire, yes, I believe it does, as you say, go directly to pin 5 of the CCU. You could test for continuity between the spade and pin 5 socket. Maybe something pushed back?
I guess the '91 harness got that included, because my '91 map shows a splice into the black/blue.
Now, checking for signal is a little more tricky. The VSS is a very low duty-cycle pulse, a very short one comparatively for visual observation. I think 1.5mS.
Anyhow, I tried once to see if a cheap LED circuit tester would pick out the VSS pulse, but I could not see it. Didn't try real hard, because I have an old oscilloscope in the garage for an easy next step. Maybe if dark enough and your eyes are better than mine, you could see it with an LED. Remember, I have the benefit of being able to easily substitute the differential sender signal using a 60Hz wall wart or a tone generator app on a phone, so I don't have to jack a wheel off the ground. I suppose that tone generator approach could be used to follow the cruise feedback action, but I've never had occasion to try it.
--
Art Benstein near Baltimore
We childproofed our homes, but they are still getting in.
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Hi,
I see it's over a month ago that I started this thread. I don't know where the time goes, although I did just take a week off to go fishing and pick blackberries.
I caught a lot of both.
Anyway, it's working now and the fault was a result of my blundering.
After swapping both the stalk and the CCU without any change, I figured I'd missed something and started over. Looking at the pedals with the pumps operating on external power, the operating 91 seemed to act faster and more forcefully than the 90. Swapping the pumps didn't change that, so there had to be a vacuum leak somewhere.
I don't know why I didn't try this earlier, but simply putting my finger over the disconnected brake switch hose with the pump running made the pedal respond a lot better. I definitely had continuity across the pins, and I guess that made me wrongly assume the vacuum valve was fully closed. Apparently not.
The leak was tiny. I could tell by holding the vacuum with my tongue where it took at least 10 seconds to be noticeable. One more turn on the switch was enough to make it function, and the cruise couldn't be better.
I'm curious why it didn't even attempt to operate with a slightly reduced vacuum. I had jacked up both rear wheels on the 91, hoping to observe the pump running but I couldn't get it to hold. I pressed the 'SET Speed ' at 40 mph and the pedal would move, but it would over run and then shut itself off at about 50. I'm wondering if it has an abort function if it doesn't see it following the program.
Anyways, despite all the dinking around, I did get to learn about a system I knew nothing about, so I'll consider an investment in time that might be useful in the future. This late cruise version is by most accounts the best, so I'm going to keep a look out for parts to install one into my non pre-wired 88. It shouldn't be too much trouble, as far as I can see.
Sorry to have dragged this on so long, and many thanks for all the help.
Peter
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I know it's all contained in the main wire harness behind the cluster but don't know where it terminates to ground. I would think it also pickup other grounds throughout the harness.
Dan
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Got a chance to track this down using a meter and wire cutter instead of opening up harness vinyl.
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Art Benstein near Baltimore
A cartoonist was found dead in his home. Details are sketchy.
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Also this:
Lousy photo, but reference on Bentley map is p390-52 section I-6
I plugged a cube relay into it, temporarily. The headlights are on with the ignition switch regardless of the headlight switch position. I'm quite sure the method was changed in 1991 to a jumper wire.
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Art Benstein near Baltimore
How does Moses make his tea? Hebrews it.
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Hi Peter,
Yeah, Bentley picked a poor one to copy from Volvo's documentation. Can't even spell "vacuum."
I have a '91 map and a '90 240 with cruise and it matches. I'd scan it for you, but the '93 late version green book map at volvowiringdiagramsdotcom has the same map as my '91 and all the wire colors agree. Only difference is where they show the PAL fuses at the battery. Starting on page 120.
Sounds like you did a pretty thorough job checking. If still needed, I can chase down that black wire termination. And as to the mystery relay socket, I know we solved that not too long ago here on the BB, but it escapes me what the simple reason was for that stub. It was not for intermittent headlight wipers I'm pretty sure! ;-)
Let us know your progress.
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Art Benstein near Baltimore
Be wary of the man who urges an action in which he himself incurs no risk -Joaquin de Setanti
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Hi Art,
Wow, that green book's a keeper for sure. I'd wondered where all those fabulous drawings were coming from. Now if I could only learn to read it.
It seems that the interrupter current piggybacks on the brake lights hot wire, and then goes through the bulb's filament to reach ground. If that's correct it must be a very low voltage in order not to flash the bulb. Then when the brake light switch sends 12 volts into the circuit, the low voltage current gets stopped or pushed back and the CCU shuts it down. Am I at least close with this ?
It doesn't seem like this would be the ground for the pump motor. Despite it's extensive ground location reference, there's not a peep out of the green book about a cruise control ground except for the one above. What is curious is that it states in the CC Functions that " the cruise control is normally grounded through the brake light bulb." Does that mean normal operation as opposed to tuning the switch off ? Or something else.
I didn't mention it in my original post, but I also took out all the seats, carpets and anything nearby that wasn't welded down for cleaning. In it's previous life the car had kids, and the kids had fun. I pulled out at least a gallon of beach sand and a thousand sticky green pennies. I undid numerous grounds to clean around them, and it wouldn't surprise me at all if one didn't get put back on.
I'll keep poking around at it and let you know what I find. I probably can't do much until next week sometime.
thanks, Peter
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You're right, that map leaves out one important piece of physical information -- where is the black wire from pin 8 of the controller grounded?
That's the "ground" you're looking for. The description talks of "ground connection broken" when you step on the brake pedal, but that verbiage misleads to thinking that removes power from the cruise. No, you understood it correctly, the brake pedal connection only samples a bit of current to sense whether the brakes are being used.
It offers a 12-volt potential at a very tiny current to the brake lights at the brake light switch, well below that which would light them up, but it follows the path through the lamps to ground. That's what they mean by "grounding" in the description of operation. When the switch does light them up, that tiny current ceases to flow because the switch provided a 12-volt potential, leaving no potential difference. Logic inside the controller turns off the cruise function.
As James mentioned, you could kinda yank on that black wire from pin 8 of the controller and see where it goes. I don't imagine it could go too far, because these things are installed separately as accessories. Somewhere I came across instructions, I think. Anyhow, in the next few weeks I need to have that area apart on my grandson's car, because I want to return his '90 cruise-control turn signal after repairing it for the high-beam switch failure. He currently has a non-cruise stalk in place, because that's all I had in the junk box.
If you can't see where it goes, another method to check it is using an ohmmeter with the car turned off, or measure for voltage on pin 8 when the car and cruise is on. If you see 12V there, you know the wire is loose.
Some additional resources:
http://cleanflametrap.com/dash.html
http://cleanflametrap.com/brakelights.htm
--
Art Benstein near Baltimore
Q: How do you pick out a dead battery from a pile of good ones?
A: It's got no spark!
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Hi Art, and Dan and James if you're still there.
I haven't had a chance to get in there as yet. The car's in daily use and I'm busy with other things, but it may interest you to see some of the intelligence I've gathered in preparation for the invasion.
I went on EBay and searched 'Volvo 240 Cruise Control' and there were a lot of people selling the kits with some good pictures.
Along with the control box, pump, pedal valves and stalk, there's a short harness, maybe 3 or 4 inches. It has a white connector to the box and 2 pigtails. One ends with a black 4 pin connector that mates to the stalk harness, and a black 8 pin is on the other one.
The sellers are saying that all 90-93 240's are pre-wired at the factory. That means no ground wire is provided, and the wiring for the 8 pin terminal should be in every car. Because this edition of cruise is quite trouble free and as you say, it's easy to test for ground , I would think there may be very few people who have ever had reason to search out it's physical location.
Last week-end I was in an area where I have an acquaintance, and at one time he had a 92 parts car so I stopped in to see if he still had it. He told me he was going to scrap it as soon as he got the tranny out, the same thing he told me about 5 years ago.
We went and had a look. Up on blocks, the driver's door, seats, steering wheel, cluster and glove box all gone. All the plastic below the dash as well. Couldn't be better. It took about 2 seconds to locate the 8 pin connection sitting right over the steering column. A non-cruise car.
Tugging at the black wire is out of the question because the 8 wires only have about an inch of freedom before disappearing into a main harness.
He went for a meter while I disconnected all the grounds at the console and at the floor beside the shifter, about 12 of them. There was no indication between the black pin and any of them, except one read 13 ohms. I have no idea what that means, but that ground traced to the OD relay.
I asked him if he had any plans for the harness and he said, "Have at it." and handed me his well-honed folder.
From their lay, the wires looked to be coming out from the left, driver side, but a little slicing revealed them making a 180 at a big Y in the harness and arriving from the right. Obviously a ploy to deceive. I thought, 'Nice try, Volvo', to myself. I made a mental note to advise Old Duke down at Stinking Creek.
I had the black wire firmly in my left hand now, and continued slicing with my right. It was an 18 wire bundle and it contained 2 other black wires besides the one in my hand. We removed the remains of the aftermarket radio, slicing the sheath until the bundle divided into 3 just at the glove box opening. All 3 black wires then went into one of these smaller sheaths, and descended behind where the passenger left side kick panel would have been.
The 3 wires enjoyed a very elegant factory splice along the way, and a larger single black wire exited the sheath, finding ground at a 10MM headed bolt near the firewall; just a little forward and below the white vacuum bottle. This bolt serves to secure the bracket that's under the heater core as well. There was another black wire at this bolt which entered the engine compartment to the left of the ICU.
So I found the secret inverted T of a ground, potentially known by only a single installer in Guttenberg, right? Not so fast.
I went over to my 90, pulled off the panel, lifted the carpet, and.... nothing. Zilch. Nada. Just another stupid 10mm bolt head. To make matters more confusing, I went home and looked at my 91 and found only the black wire that goes through the firewall at that location.
So for the record, here's what I know.
I don't know where the cruise is grounded for 90 or 91.
I do know where the cruise is grounded for 92.
The 93 Green Book wiring diagrams suggests there's a ground for 93, but they don't know where it is.
I hope nobody takes offence, but I find Volvo's grounding policy to be a little bit whimsical. On the other hand, I guess we should all be thankful that they didn't spread unnumbered fuses throughout the car, under the carpets and behind different panels.
Anyways, I'll pull the cluster and go at it from the connector when I find some time. The car needs a timing belt ASAP so it might be a while. We don't use the cruise around here, but there might be a trip coming up in September.
Regards, Peter.
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Amazing story! Quickly, did I miss something, or did you ever get a chance to put your ohmmeter on pin 8 of your 1990's socket? I'm aware the harness changes between 90 and 91, but rather ignorant of the changes 91-92.
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Art Benstein near Baltimore
"...real expertise is never appreciated. People would always rather muddle along in their own dim, blundering way than have someone else point out where they were going wrong--even if that other person is clearly brighter." -Jeff Lindsay
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No Art, I have not been into my dash. I looked briefly at the grounds in the center console but I restrained myself from going further.
I have a pile of saw logs that I cut last winter, scaffold quality red spruce, and the bugs are now into the bark. If I don't saw them immediately I'll be very sorry, so 240's absolutely verboten for me for at least a week. Maybe longer if the weather gets bad.
Peter
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Is there a reason you need to find where it is actually grounded? If not testing for ground at the connector should tell you what if it is adequately attached.
Dan
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I think I understand where Peter's going with this. The 90 is in service, and not available for unscheduled or ad-hoc tinkering, but he had a serendipitous opportunity to look at that 92 and 91 without need to put things back in shape, hoping he'd discover the ground was in an area he remembers working before. I like his thinking. Iatrogenesys.
Learning from Peter's analysis that the cruise option does not include wiring a new ground gives me good reason to doubt I'll be able to trace its origin next week when I have the cruise-equipped 90 to work on. If it disappears into the cabin harness, I expect there will be splices within the vinyl and no easy way to ascertain the point where the wire meets the chassis. It is not listed in Volvo's list of ground locations -- at least for the cruise function. I'll give it a try though, when I change the stalk next week.
No such thing as a cruise control emergency...
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Art Benstein near Baltimore
Those of us who spent our allowance at the five and dime think we are getting a bargain at the dollar store.
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"If it disappears into the cabin harness, I expect there will be splices within the vinyl and no easy way to ascertain the point where the wire meets the chassis."
I believe this is true as I stumbled across several of these splices while dismantling a wrecked 91 I had a couple of years ago.
Dan
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Have you tested the black wire that you think is a ground to see if it actually goes to ground?
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Hi James,
I have only seen this black wire on a wiring diagram. The control unit from which it originates is in the bowels of the dash and I'm not eager to go in there as yet. It may come to that.
My hope is that it might terminate in an easier to reach location. If I find it, I will surely test it.
regards, Peter
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