Need help-electrical problem

[Ed Hill]

Have been reading the board for a while, Impressed with the knowledgeable people who participate on this forum. This is my first attempt to post here. If you can help solve my problem I would appreciate it.

Truck: 2002, 3500, 4x4, Dmax w/Allison, Extended cab, 7500 miles. Been to two dealers - one of them twice.

Problem: Fuse for stop lights and turn signals blows intermittently.

History: (1) Trailer attached to truck (not the first time) fuses for stop and turn blew. replaced fuses. (2) A few weeks later without trailer stop light fuse blew. replaced fuse. Carried truck to one dealer - could not find the problem. Thought it might have been water in the trailer connector and caused a short. Had gone through heavy rain the day I discovered fuse blown.
(3) About 1 week later stop light fuse blew again - no rain or trailer. Took truck to different dealer - spoke to GM - said they knew of one other case like this. Replaced the multifunction switch (turn signal switch). (4) About 3 weeks later (yesterday) - no trailer or water - stop light and turn signal fuses blew. Returned truck to 2nd dealer - the one who replaced the switch. Service manager said he was on phone with GM for about 1 hr. today. Only thing they could subject was that it was the trailer. I told service manager I was not pulling trailer. They are going to check it some more tomorrow. Could not find anything wrong.

Any one had similar experience or have a possible solution? Thanks.

[cogburne]

Trailer lights are seperate circuits all the way around. Are the trailer or truck light fuses blowing? One should not effect the other. i.e. massive trailer wiring meltdown would not disable vehicle lighting.

[mark45678]

water a loan will not provide a good ground to blow a 20A fuse at 12 volts. I would guess there is a problem with a wireing harness being crused if the truck has low miles. or maybe in the blinker switch.

[odoh]

Hmm-m, grasping at straws here as I've not experienced same but does it do it when the brake controller is disconnected? Any specifics on the controller etc? ~ odoh

[DmaxMaverick]

There is a real good chance that your hazard signal switch has gone south (even though you've probably never used it?). The brake and turn circuits go through it. I've heard of several of them on the 99's and up with this problem. Suggest it to your s/m. Be tactful though. They hate it when you know more than they do.

[Ed Hill]

Thanks for the responses. Any others appreciated.


Replys to:

DmaxMaverick - will test hazard signal switch.

odoh - brake controller not installed yet.

mark45678 - the blinker switch has been replaced.

[Brandenburg]

On mine, the hazard switch is built right into the turn signal/multifunction switch so if that has been replaced, the hazard switch has probably been replaced as well.

[EIS01]

I had my hazard\blinker switch replaced, my blinkers did not work or hazards. I believe the switch is built together. So you had both replaced at the same time. Mine did not blow any fuses. Just quit working. Good Luck, Kevin

[ 05-07-2002: Message edited by: EIS01 ]</p>

[Ed Hill]

Update: Thanks for the information you all sent me, I went back to the dealer today. They did not finish with it maybe by tomorrow. Thanks again for the quick response and valid information.

[Ed Hill]

Update - hopefully the last one for this problem. Got truck back from the dealer today. The multifunction switch (turn signal, cruise, etc.) was replaced- 2nd time in 4 weeks. It is working today.

They said that if the haz.flasers were on for several hours, enough heat to cause things to melt. But if this wa the problem, they could put a relay in and reduce the currant flow through the switch.

Again, thanks for the help all of provided.