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A simple failure really and quite common, fuse #7 gave up the ghost with a partially melted end cap. Fuse 7, however is one I think is rather important, ie. brake light power, especially in full go and slam the brakes freeway traffic.
The only reason I noticed that the fuse was failing is that every time I hit the brake pedal, the tire pressure monitoring system display that I added winked out, which is also powered by you guessed it fuse #7.
I can assure you that in this morning's traffic, if I hadn't noticed, someone from behind would have let me know with their front bumper!
So on the drive home this evening I thought about this simple/common failure and realized that in a car that doesn't have mods, the driver has no way of knowing if the brake lights are out due to a failed fuse (bulb failure circuit won't report this failure)... hmmm....
So, for those of you who don't like being rear-ended and it being your fault, perhaps adding a low brightness green indicator LED somewhere on the dash that is hooked to the output side of fuse 7 might be a good idea... LED goes out, fuse is gone... no brake lights! That being said, a better idea might be to hook the LED into the output of the brake switch so the LED only comes on when the brake is pressed, if it doesn't come on, there is a problem!
Yes, once I noticed the problem, I pulled off the freeway, cleaned the contacts and installed a new fuse.
Just a thought, hopefully it will prevent some damage and or injuries out there!
jorrell
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92 245 278K miles, IPD'd to the hilt, 06 XC70, 00 Eclipse custom Turbo setup...currently taking names and kicking reputations!
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If I could get access to the image library I would attach a pic. It is a blown fuse indicator circuit. It is simply an LED in series with a current limiting resistor. Connect the circuit across a fuse to be monitored. If the fuse blows the LED lights up. For a red LED, a 680 ohm resistor is fine, when used in a 12-volt circuit. Or you can use Radio Shack 276-270 LED which has a built-in resistor.
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1986 Volvo 245
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Let's see if this works...
[IMG]http://i309.photobucket.com/albums/kk371/newrev77/BlownFuseIndicator.gif[/IMG]
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1986 Volvo 245
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To display photos from a Photobucket album:
Pass your cursor over one of the thumbnail images. Then click on Link Options. Check HTML for websites and blogs Full size and then Save.
Now when you pass the cursor over a thumbnail it will display the HTML code in the box. Click once on the box to highlight it (it highlights the entire link with just one click even though you can not see all of it)
Now copy the link using Control C and move to your brickboard post and use Control V to paste the link into your post.
When you Submit Message it will display the image from the album.
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oops! - guess i shoulda read ALLL the way down the thread and see that Art had the same idea as I mention below:
I got so tired of the lights flickering and worried that my brake lights weren't coming on when needed... I pulled the cover off the 3rd brake light and cut a 12mm hole in the roof of the cover and put it back on... Sat in the car, applied the brakes and the hole shined light to the rear window. I was able to see the true condition if they worked thru my rearview mirror. To this day, I still catch myself just checking the method and people think I'm brake-checking them. Flawless...
The thing is... I'm not sure if the wagon models have this capability. It'd be nice.
2cents
TIm
'92 244 NOW w/ M47 (Hydra, turbo bars, bilstein, urethane bushings)
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I had the same problem a couple of months ago. Didn't know it until a guy yelled " heh buddy no brake lights". I cleaned all the contacts with a tooth brush and WD-40 and applied di-electric grease. some of the loose contacts I gave a lite squeeze to increase contact pressure. I think Art's suggestion about the brass fuses is a good one.
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John:
Just wondering why the fuse melted. Could it be that the draw from the brake switch and 3 brake lights with othter components on that circuit is neat the limit of fuse #7 and by adding your mod of tire pressure monitor system you are nearly exceeding the fuse limit?
Not sure just wanted to know why the situatioin occured.
Thanks
Al
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Al,
The TPMS system only draws 100mA, so it wasn't a "significant" contributor as a white fuse is rated at 8 Amps with a typical peak rating of 16 Amps. Note that the fuse did not fail in the thin center spot where it normally would if the fuse was overloaded.
The failure occurred at the pointed tip of the fuse where it makes contact to the fuse holder. When I removed the fuse, there was corrosion (and melting) on the fuse as well as white corrosion on the fuse holder. The root cause was corrosion, the secondary was weak spring pressure on the part of the fuse holder, probably due to heat generated by the oxidized fuse contacts which can cause the brass spring contacts to "relax".
Three plus years ago when I put this car together, I cleaned all fuse holders/contacts and installed new fuses, apparently not checking/cleaning fuses and fuse contacts for that period of time is a bad idea! For now at least, I'll move the fuse cleaning to a 12 month cycle.
jorrell
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92 245 278K miles, IPD'd to the hilt, 06 XC70, 00 Eclipse custom Turbo setup...currently taking names and kicking reputations!
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I may be dreaming here, but I've noticed better performance out of my vehicle with the 25A fuse in the engine compartment all shined up as well. My favorite two components for doing all the fuses: A Dremel tool with a small brass wire wheel, and a tube of Alconox (similar product as mentioned elsewhere). I fortunately don't have the high humidity problems that many other parts of the country experience.
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John:
Thanks for the clarification. It seems that we all should pay more attention to all the electrical connections that are exposed to corrosion. Grounds, fuses. solinoid terminala, lighting connections, etc.
Perhaps we ahould use "Penetrox" on all these connections to prevent corrosion.
I think Art's suggestion of the brass/ceramic fuses is a good idea as well.
BTW if the fuse is rated at 8A with higher "16A" on a momentary basis what is the current rating of the cable that is in the fuse #7 circuit?
Thanks again
Al
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Following that root a little further may lead to a reason for the moisture. But if you can blame it on the Carolina humidity, I guess there's not much more than annual maintenance for action.
However, the brass fuses seem to be less prone to galvanic corrosion -- no white stuff like the tin -- and that is just what FCP is peddling these days at a reasonable cost on ceramic substrate.
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Art Benstein near Baltimore
No one ever says, "It's only a game", when their team is winning.
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I blame the extra moisture from the wet feet from rain or snow. Puddles on the floor boards. Chill of the metal parts of the panel.
Then to, there is that air vent behind it that I never use!
Phil
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Okay Art, I'll bite, where does one get the brass fuses, as my replacements are the old factory tin flavor off the Volvo production line! In short, ALL of my fuses are tin and I'd rather have brass to avoid galvanic reactions.
No water leaks, just 95 degrees and 98% humidity! We are talking weather that can overload the AC condensation drain tube on a daily basis.
jorrell
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92 245 278K miles, IPD'd to the hilt, 06 XC70, 00 Eclipse custom Turbo setup...currently taking names and kicking reputations!
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John, I wasn't taunting you with the brass fuses. I mentioned in my post these are what FCP is peddling these days. On a ceramic substrate. My order was within the last six months easily.
Man, I know what long days at the office and three hour commutes will do to one's focus.
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Art Benstein near Baltimore
Never raise your hands to your kids. It leaves your groin unprotected.
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Art,
My apologies for not fully reading your post... my bad. I'll have my much better half call FCP tomorrow and order a ceramic/brass fuse set for a 240... actually two of them... doesn't hurt to have spares!
Once again, thank you!
jorrell
ps. Writing 400 pages of product requirements, specifications, test procedures, test results, and marketing bling in three weeks will make anyone go cross-eyed! And trust me, last night when I popped the hood on "Bleen" I was certain she had two distributors! But then again, tomorrow night the Volvo grease therapy weekend starts! All will be good!
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92 245 278K miles, IPD'd to the hilt, 06 XC70, 00 Eclipse custom Turbo setup...currently taking names and kicking reputations!
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Hi John,
On a Mitsu I used to have I drilled a tiny (probably 3/32) hole in the front of the high-mounted brake light, so I could see, in the rear view mirror, exactly when the brake lights came on with pedal pressure. I can't remember why.
Some of the older 240's with the Dana cruises, set the lights-on reminder chimes to ringing when the brake light fuse was open. Archives are full of this. Folks thought it was an undocumented brake fuse alert, purposely built by Volvo. Little Easter egg.
My daughters become aware of their brake lights not working when they have to use the shift lock release to get their car moving. I take it you didn't import this lovely feature when you went manual to auto.
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Art Benstein near Baltimore
Do Lipton Tea employees take coffee breaks?
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Art,
You are correct, I did not install the failure prone OD relay system, I just ground a fluid path into the face of the OD solenoid... no leaks, no drips, no errors.
The shifter bucket I'm using is out of an 89, so no interlock solenoid, that being said, the brake lights worked great when I left home this morning, the fuse gave up after a violently rough patch of pavement on the entrance ramp from I-40W to I-77S!
I like your idea about drilling a hole in the RCBL cover, that way a failure would be visible through the rear view mirror.
jorrell
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92 245 278K miles, IPD'd to the hilt, 06 XC70, 00 Eclipse custom Turbo setup...currently taking names and kicking reputations!
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Hi John,
Perhaps you can post about the pressure monitor. That sounds like a safety accessory befitting a 240.
Also, do you have any top-of-the-head ideas about a pressure reference or standard? I noticed, last weekend, when my daughter handed me her glove box dial type pressure gauge, she needed air in all four. (Cleaning the brake dust from her alloys is an act of love akin to washing a woman's feet for her, even if this was a bimmer.) But when I aired them up to what my tank gauge claimed to be 32, her gauge said 40. I brought out every gauge I owned and found repeatable readings from 30 to 40, settling on a final value by "consensus". What should I be doing?
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Art Benstein near Baltimore
Did you ever notice when you blow in a dog's face he gets mad at you? But when you take him in a car he sticks his head out the window.
-George Carlin
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Art,
The TPMS system I installed was from IPD... but it seems they don't carry it anymore, perhaps a call to them would be in order. The reason I installed the system was that I destroyed a 2000 mile Yoko ES-100 205x50x16 on the right rear without knowing it was flat... installed and balanced $150 for the replacement. The TPMS system puts a pressure and temperature transmitter in each valve stem, all of which communicate to a small display unit by RF at the top of the windshield. So far, it has saved me two tires over roughly two years due to punctures. If the pressure drops below preset limits, or the tire temp goes too high, the display unit beeps "politely" to let you know what's happening and displays the pressure of the offending tire.
When it comes to hand held gauges, I have one mechanical "Nascar style" gauge, regardless of temperature, it is within a few PSI... just don't leave it laying in the sun first, then its way off. I'm not a fan of the stick style pressure gauges, they are air pressure vs. friction, so if you add oil or grit to the "stick", say goodbye to accuracy.
My preference is a digital tire pressure gauge as the majority use a self temperature compensating circuit to compensate the pressure wheatstone bridge. A few years ago, I had three of them ranging in price from $10 to $50, regardless of temperature, they all agreed with one another within 0.3PSI. That's my 2 depression dollars worth of advice!
jorrell
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92 245 284K miles, IPD'd to the hilt, 06 XC70, 00 Eclipse custom Turbo setup...currently taking names and kicking reputations!
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Hey Art I use the stick tire guage and they seam to be very accurate as I check against the compressor guage. They must be kept clean as they are sensitive to friction.
On another note i replaced all the ceramic fuses with glass from IPD on my 87 in in 1993 and have only one failure,number 7 brake lights,someone notified me that my brake lights were not working.
Another easy test is when backing up at night apply the brakes and look in the rearview you will see the red even thru the halogen back up lights
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I also got the sense the stick was better. No science, just feel. I'd like to know more.
On that other note, fuse 7 (or the brake light fuse) will fail on all our cars eventually. Watch the element flex as you step on the pedal. It hardens and cracks right in the middle, unlike John's corrosion failure.
I have some of them, but I'm not fond of the glass fuses because the element can disconnect within the end where you can't see it. This is the legacy of the 3AG (1/4") fuses. In manufacturing, sometimes a flux joint is made there, giving rise to the joke about fuse testing at 100%. There are good and bad points to all automotive fuses. I pity the poor 7/9 owners when their molded ashtray fuse panels catch fire.
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Art Benstein near Baltimore
E-lamps are electrodeless fluorescent lamps.
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