Brake light problems

[Benc]

The rear brake lights on my truck quit working (trailer brake lights also), but the CHMSL, turn signals, and tail/marker lights all still work. It seems a little odd to me that only part of the brake light system has quit. Has anyone run into this before, or have any suggestions for possible problems/fixes.

thanks for your help

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1997 2500 SLT Reg cab LB 4x4 5-spd 4. 10 limited slip stock, but hopefully not for long

 

[Joe G.]

If your '97 is like my '95 the fuse for the STOP LAMP is at the lower right in the fuse panel in the driver's side of the dash. If that's ok, then maybe we can guess at what else it might be.

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Joe George
Eureka, CA

'95 2500 CC auto 4X4,3. 54,Combo EGT/boost guage,custom switch panel,PacBrake,TST #5,DTT TC/VB,Automatic motorhome steps on both sides,Foldacover hard bed cover,Cummins chrome kit,Black steel grill guard,Front hitch receiver, KDP 160,000-NM-WT Insurance

 

[Benc]

The fuse is ok, and I assume the switch is ok too, since the CHMSL still works.

Any guesses would be great, I'm stumped, and I really don't want to take it to the dealership.

Thanks,
Ben

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1997 2500 SLT Reg cab LB 4x4 5-spd 4. 10 limited slip stock, but hopefully not for long

 

[Joe G.]

Ben,

Your gonna need a meter now. Do you have a service manual? That's almost a gotahaveit for something like this. Saving a trip to the dealer will pay for it right away. My '95 service manual shows that circuit is connected to pin 13 of the "turn signal and hazard flasher switch (part of multi-function switch)". The CHMSL gets its signal directly from the stop light switch before it gets to pin 13. Output to the stop lamp/turn signal lights is on pins 12 and 15. You need to check that when the brake pedal is pressed that there is 12v on pin 13. If there is then check either pin 12 or 15. If you have 12v at 13 and none on 12 or 15 you have problems in the multi-function switch or a dirty contact at pin 13 at connector C210. This is from my '95 manual so it might be a little different on yours.

 

[Benc]

Problem fixed

Just in case anyone was concerned, I got my brake lights working again. I'm not quite sure how, but if something works, why question it, right.



Anyway, I pulled the multi-function switch out, tested it with my new meter, and everything tested ok. So I scratched my head, and tested it again, still ok. I then tested the the power in from the brake pedal switch, and that was ok. Then I sat down and really studied the service manual, looking for something I missed, but I didn't find anything. So as a last resort, I plugged the switch in, and checked the brake lights again, and the darn things worked.



The only thing I can think of is there may have been a bad connection at the multi-function switch, that was fixed by being unplugged and then plugged back in.



Thanks for your help

Ben

 

[DennyDay]

Benc - - - The origional electrical fix, un plug and plug back in - - drives ya' nuts. . The real problem was FM. (the second word is magic!)