Took the relay off to troubleshot no cooling fan. found the middle connection corroded beyond recognition. It had fallen apart actually. This probably came from a battery over charge incident with the PO (the battery box is rusted right out). I have a white w/blk tracer and a blue with blk tracer. Which one goes to which side? I got a 93 960 relay from a junkyard but the wire colors are different (assume it is because it had the auto climate control).

If your relay (actually 2 coils in there - Hi and Lo speed) has the reminals identifies like the diagram shows:

White/Black goes to terminal 2B (Hi speed coil)
Blue/Black foes to 1B (Lo speed coil)

You didn't ask, but:
Green is on 1C to Fan low speed
Big Red on 1A from battery + fusible link
Smaller(?) Red is on 2C to Fan high speed


--
Bruce Young, '93 940-NA (current), 240s (one V8), 140s, 122s, since '63.

Bruce, I might have actually fixed it but forgot an issue. I forgot that the AC has to be functioning on a 93 940 for the fan to work. When I was checking running the car before. I was checking each wire on the rad mounted thermo switch with a test light and had no power. I tried to jump the switch by connecting the wires individually to the Pos pole of the battery again with no joy but I do not think I actually shorted or jumped the two wires coming from it directly. I was reading the other posts on the forum and came across this one you had posted on

http://www.brickboard.com/RWD/index.htm?id=1426366&show_all=1

DUH! I went out and turned the key on but did not start the car and when when running a jumper wire between the two, the fan now roared into life!!!! This confirms the cooling relay connection and possibly the relay was/were trashed and my work (at your direction) possibly fixed them. So, I have an appointment to recharge and eval teh AC on Thursday. In the mean time should I connect up the jumpers for operating the car? Like driving it to the AC shop?

Carl,

Go Here and click the DOWNLOAD button to get the PDF file.


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Bruce Young, '93 940-NA (current), 240s (one V8), 140s, 122s, since '63.

"I forgot that the AC has to be functioning on a 93 940 for the fan to work."
• No, it doesn't. Sorry if I mislead you there, but the radiator thermo-switch will "pick" (energize) the Fan Control relay anytime it's hot enough.
[That's why you may hear a fan running when you walk by a recently parked car on a hot day.] More later.

1) "When I was checking running the car before. I was checking each wire on the rad mounted thermo switch with a test light and had no power."
• Something wrong there. The white/black wire should always show 12V present,
"reading" thru the fan relay's coil, which is directly tied to battery + via fusible link wiring. This is also inconsistent with your later results at #3 below. More later.

2) "I tried to jump the switch by connecting the wires individually to the Pos pole of the battery again with no joy but I do not think I actually shorted or jumped the two wires coming from it directly."
• I'm surprise (and can't explain why) there was no sparking when you "shorted" the white wire to the + battery pole, since that wire goes straight to ground—or should. More later.

3)"DUH! I went out and turned the key on but did not start the car and when when running a jumper wire between the two, the fan now roared into life!!!! This confirms the cooling relay connection."
• Yes it does. But makes #1 above confusing, when neither wire had power.

4) "So, I have an appointment to recharge and eval teh AC on Thursday. In the mean time should I connect up the jumpers for operating the car? Like driving it to the AC shop?"
• I'd say no need for that. I haven't heard my fan come on automatically for years. It's NOT supposed to run whenever the AC is on, unlike the 240 AC as I understand it. However I did run a "jumper" from the thermoswitch (Black wire terminal) to an added toggle switch on the dash leading to a ground point. This lets me turn the fan on High, when idling or in slow traffic, for better AC effect.

And now the "More later" — my DUH moment.

COPY this URL...
Wrong URL, and I forgot that a PDF file doesn't have one anyhow. so you can't open a second browser window, etc. Anyhow, the list below describes each numbered item that I thought you'd see. If I can find a source for that PDF I'll be back.

2/11 is the Fan control relay, with 2 output wires to 6/29, the Fan. The Green wire is for Low speed, Red for High.

7/38 is the Brown pressostat in the group of three on the bottom front of the condenser. It will trigger Low speed should the AC High side pressure exceed 261 psi and remain closed till pressure drops below 203 psi.

7/14 is our Radiator thermoswitch for High speed fan operation. I don't know what temperature it takes to close it. My panel toggle switch is wired in parallel with 7/14.

7/40 is the Gray condenser pressostat for High speed fan when AC high side pressure goes above 334 psi and stays closed till it drops below 276 psi.

Whew!
--
Bruce Young, '93 940-NA (current), 240s (one V8), 140s, 122s, since '63.

Easy for me to overwhelmed and confused. IS the functioning of the thermo switch called into question? That is an easy replacement if so.

Carl

"IS the functioning of the thermo switch called into question?"

Not necessarily. As I noted in my post above, my Fan hasn't kicked on for years, since I now turn it on from the dash in slow traffic. I don't know what the temp the thermoswitch closes at. If you knew the operating temp you might test (carefully) it with an electric heat gun.


--
Bruce Young, '93 940-NA (current), 240s (one V8), 140s, 122s, since '63.

Got what I assume to be good same model relay from a 93 960 in a yard. I wired it up with the blue on 1 and the white on 2. Good solid connectors using a quality crimper, greased the connections. Put it back on the wall. Cleaned the ground post and clamp on the car and greased that ((standard British car stuff). Hooked up the ground cable (neg) to the battery and got a spark (humm, that is not good I think). I have never had that connection off on this car before so it is hot and I am very tired so I say "what teh hell" and continue. Car started up fine and ran fine. Car temp guage gets up to just past half (maybe 6.5 on a 1-10 scale) infrared thermometer showed 190 on the rad. 190 (+/-) on the upper and lower hoses. I got 190-200 on the block and at about this time, coolant came boiling back up into the reservoir (cap was loose at this time and a bunch dumped out).

I probably cooked the relay (cost less than $10). Not sure if the spark was an ongoing problem or due to wires mixed up on the relay middle connection. Normally isn't teh spark at connection when you have the poles mixed up? I never took the Pos lead off so obviously this is not the issue. My lack of mechanical aptitude is showing here on the board but I do try and learn before sending it to a shop (appointment made for Thursday)

Bruce, your help is GREATLY appreciated. I want you to know that I really and grateful to you for your continued patience.

Carl

"I got 190-200 on the block and at about this time, coolant came boiling back up into the reservoir (cap was loose at this time and a bunch dumped out)."

That would concern me. Doesn't sound normal, but then I've never run mine hot with the cap off. Not relevant here, but did switch the green cap for a lower pressure black one to male life easier on the radiator.

I'd suggest you try a new posting on this one.
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Bruce Young, '93 940-NA (current), 240s (one V8), 140s, 122s, since '63.

Too add, It got too dark to take the middle relay connection off and rehook the battery to see if that is what caused the spark upon connecting the neg pole. The big red wire connection to the Pos pole clamp may be loose and about to break. I have some time tomorrow in the late afternoon/eve to remake that if needed.

Is this one on the back burner for now?

I don't recall much sparking when I disconnect the battery negative. Maybe this too should be a new post if it continues or battery runs down. FYI, my '93 sometimes sets unused for a week with no problem starting.


--
Bruce Young, '93 940-NA (current), 240s (one V8), 140s, 122s, since '63.

It starts fine Bruce. Just tegh spark kinda got my attention when connecting the grd back up. The link you posted for the PDF's just takes me back to this thread. Pretty sure I was doing that right.

I assume it is not unheard of for the car to over heat in hot weather at idle with no cooling fan.

Tired of beating my head against the wall. Me taking on auto electrics is risky at best and teh fact I have not made anything worse is a victory. I did find the compressor does spin when energized. I did find the cooling fan comes on when the female wires coming from the radiator mounted switch are jumped. I did find after replacing the cooling relay and the middle plug which had both received damage from battery acid, I now 12+v at the White with black tracer wire. However, When I connect a test light to it using the same ground I did with the MM, the fan comes on. I do not understand that one. Today it was in the 90's so I used it as an opportunity to see how the car cools with the fan. I had to plug in the jumper wire each time I drove the car but that was fine.

Tomorrow, it goes to a friend's Radiator and AC shop. He is a very skilled person who hates all the new radiator places out there popping up being run by people who do not really understand Cooling and AC. He will look at it, probably give the system a charge and see what happens on that end.

Is it highly possible that the cooling fan switch and sensor mounted in the radiator is bad? There is another temp sensor mounted on the block under the intake is there not? My mechanic had showed that to me but I cant remember what it is for.

Bruce, I would love to talk on the phone sometime to try and sort out a few things as too often I am not able to describe accurately what is wrong and where I am talking about.

Carl

"However, When I connect a test light to it using the same ground I did with the MM, the fan comes on."

The test light (a fairly low resistance) connected to the rad thermoswitch White/Black wire is providing the ground for the fan relay coil, simulating a radiator thermoswitch that is hot enough to close.

"Is it highly possible that the cooling fan switch and sensor mounted in the radiator is bad?"

I wouldn't say "highly" -- just possible. You still seem to expect the fan to run with the AC on. But the 940 AC does NOT work that way. Be sure your AC guy understands that so he doesn't waste time on it. The fan runs only when 1 of 3 conditions exist:

1 and 2 are excessively high refrigerant pressures at the condenser.
3 is excessively hot coolant detected by the radiator thermoswitch.

My 940 has never encountered #1 or #2, and #3 only rarely but not in several years of semi-rural driving.

Call any time before 7:00 PM please. 315-893-7872 will be screened by answering machine. I'll pick up when I recognize a valid caller's voice.
--
Bruce Young, '93 940-NA (current), 240s (one V8), 140s, 122s, since '63.

"However, When I connect a test light to it using the same ground I did with the MM, the fan comes on."

The test light (a fairly low resistance) connected to the rad thermoswitch White/Black wire is providing the ground for the fan relay coil, simulating a radiator thermoswitch that is hot enough to close.

(SORRY, NOT SHOUTING HERE, JUST TRYING TO DIFFERENTIATE MY NEW TEXT FROM OLD).

THANKS BRUCE, THAT MAKES ME FEEL BETTER.

"Is it highly possible that the cooling fan switch and sensor mounted in the radiator is bad?"

I wouldn't say "highly" -- just possible. You still seem to expect the fan to run with the AC on. But the 940 AC does NOT work that way. Be sure your AC guy understands that so he doesn't waste time on it. The fan runs only when 1 of 3 conditions exist:

i DO NOT EXPECT THE AC TO TRIP THE FAN. THAT CAME FROM THE OTHER FORUM POST THAT TALKED ABOUT THE 940 FAN NOT WORKING WHEN AC WAS DOWN. WHAT I EXPECT IS THAT THE CAR WILL NOT OVER HEAT. THAT THE FAN WILL COME ON AT SOME FACTORY SET TEMPURATURE. IT IS NOT DOING THAT RIGHT NOW. BEFORE I CHANGED THE RELAY AND REMADE A CONNECTION, I GOT NOTHING FROM THE FAN SO I AT LEAST FEEL GOOD ABOUT THAT :-)

1 and 2 are excessively high refrigerant pressures at the condenser.
3 is excessively hot coolant detected by the radiator thermoswitch.

My 940 has never encountered #1 or #2, and #3 only rarely but not in several years of semi-rural driving.

I DO NOT KNOW IF THE ABBREVIATION 'DPO' MEANS ANYTHING IN THE VOLVO WORLD BUT IN THE BRITISH CAR WORLD IT STANDS FOR 'DREADED PREVIOUS OWNER'. I AM REALIZING THE PREVIOUS OWNER IS NOT AS SMART AS HE THOUGHT HE WAS AND I AM STUCK TRYING TO FIX WHAT IS WRONG AND TRY AND FIGURE OUT WHAT HE MAY HAVE DONE TO TRY AND FIX IT HIMSELF BEFORE I GOT IT (FINDING ALL THREE SWITCHES TO THE CONDENSER UNPLUGGED AS AN EXAMPLE). I WILL TRY AND CALL YOU TOMORROW BEFORE 7 AND MAYBE TELL YOU WHAT THE AC SHOP FINDS.
CARL FRENCH
ALFRED, ME