Tail light bulb kills IC pump and fans.....

[sytyguy]

Talk about your weird problems....here's what happened:

Driver side tail light had been acting up for some time (shined too bright, blinked too fast, etc...), so I replace all 3 bulbs with new ones covered in bulb grease - problem fixed. Cut ign on and flip blinker to see if it works. Hear IC fans/pump kick on (hotwired), and immediately shut off. So, I....

Check fuse block for blown fuse - nada
Check fan fuse (spliced into headlight power feed wire) - nada
Replace IC pump relay with new one (RY-27) - nada
Check all wires at CCHE and replace 2 wire w-pack connector - nada

Finally, break out the digital multimeter and ohm out the harness at the IC pump relay. No power from ANY wire with key off, and power only at pink wire with key on. Also, no power from any of the 3 wires at the 3 wire IC pump w-pack connector (key on or off). Only lead I have is that when I plug the relay into the wires slowly you can hear the relay click/trip, signifying to me too much voltage. My next step is to trace the problem back to the tail light and see if removal of the bulbs will allow for pump/fan operation. But if it does, then WTF does that tell me? :-?

I guess my questions are:

- Have any of you (God forbid) had a similar problem?
- If so, how was it resolved?
- Anyone have a decent wiring diagram of the IC relay (or happen to know what feeds what, what grounds what, etc...)?

Any help is much appreciated....and yes, I have exhausted myself in all available manuals i/c the SyTy CD-ROM.....

TIA - Feeling a little....er....wired....

Michael Hood
Syclone #1596
GAST

 

[leroy]

I think there is a red wire that is hot. It comes from the back of the alternator through the fuse.

Jim

 

[myclone]

I had a somewhat similar prob on a S10 of a buds. Bulbs too bright, blinked too fast, blown fuses, weird elect stuff going on, etc.

Turns out he had replaced a bunch of bulbs with 1157s instead of 2057s. 1157s are the wrong ones and draw too much current.

Might be worth a look at the rear brake/signal and the front signal/running lights.

 

[Ian Turgeon]

I didnt see you mention checking the IC pump fuse around the alternator.

Agree with the weird happenings on the bulbs. You can put them in wrong it seems.

I believe the yellow wire is the switched ground to the ecm, opposite that would be a positive.. and the crossing direction, one output would be the ic pump with the opposite being the positive feed that I believe comes off the alternator.. where the fuse is.

 

[sytyguy]

And the winner is.........Ian & Dave!

Problem - Blown fusible link on the back of the alternator
Cause (I suppose) - 1157 in place of 2057

That seemed to be the one place I didn't look. Sometimes you think about things so hard that you overlook the easy ones I guess.

Thanks Ian, Dave, and Jim.

Michael hood
Syclone #1596
GAST

 

[Ian Turgeon]

boy, I dont know about you Dave, but I shore to feel damn smarter.


Glad it was that easy to find.

 

[V6 Kompressor]

Damn, 1157's were stock and oem installed in the front and rear lens housings of sy-tys... 2057's have a heavier duty element that resists jarring and vibrations of 4wd trucks.... according to osram/sylvania catalogs... I think 1157's have been used since the 50's... watch your grounds, especially in the engine compartment... if the bulb is inserted backwards, then the running light fillament becomes the turn signal/brake light... and vice-versa.... and if you try hard enough, you can install the bulb backwards....

 

[myclone]

Damn, 1157's were stock and oem installed in the front and rear lens housings of sy-tys... 2057's have a heavier duty element that resists jarring and vibrations of 4wd trucks.... according to osram/sylvania catalogs... I think 1157's have been used since the 50's... watch your grounds, especially in the engine compartment... if the bulb is inserted backwards, then the running light fillament becomes the turn signal/brake light... and vice-versa.... and if you try hard enough, you can install the bulb backwards....

Thats weird... The 1157s in his S10 would get hot enough to actually start melting the lense on the tail lights if he had to sit in traffic for an extended time with his foot on the brake. Its been years since I messed with that truck but I do remember all kinds of weird stuff going on with his gauges (fuel gauge especially) and the turn signal speed. I remember going to the parts store to get replacement bulbs since the melted tail light lenses told me the ones he had in there were wrong and I grabbed 1157s off the shelf. I got to talking to a car bud that worked there on the way to the check out and mentioned that I was messing with an S10 with weird electrical probs. He noticed the 1157s and said I had the wrong bulbs. I didnt believe him since we were always messing with one another (he was a ford guy) so he looked them up and sure enough the replacement bulbs were 2057s.

Since then Ive never noticed a 1157 in a S10 later than 86 as Ive paid attention to what # bulb is in there since the above S10 caused me a week or more of grief. That includes both sys Ive owned.

{as myclone scratches his head and wonders what the correct bulb actually is now}

 

[V6 Kompressor]

I was wrong about the 1157/2057 deal... acording to this article/fact sheet the low filament (park/running lights) on the 1157 pulls 1/10 of an amp more and even if you multiply that by 4, that is only 4/10 amp more draw, not enough to cause any problems at all. The Brake/turn signal filament is the same in both bulbs, puts out the same candle power ect... check here:
http://www.theherd.com/articles/bulbs.html the only times I have seen lenses get melted was when that brake light switch broke or went out of adjustment and kept the brake lights on all the time....

 

[V6 Kompressor]

oh yes, the reason that the fuse link burns up is usually you have an i/c pump starting to go, but it also sounds like you have run some small fans off the same circuit, thus probably borderlining the current rating of that circuit. You need to run a separate circuit for the fans, with a separate relay, fuse/fuse link ect.

 

[sytyguy]

Probably right, but the fans are drawing main power from another source (separate), and the relay receives it switch signal from the same IC pump source. Dunno if this is overloading or incorrect, but it had been working fine for 4 years like this, then just blew outta the....er....blue when I started monkeying with the lights. I'm chalking this one up to human error.

Oh well, works now.

Michael Hood
Syclone #1596
GAST