Electrics

[onlychild]

I've always had this suspicion my 94 dually has had some electrical problem I cannot seem to find. It acts like there is an excessive amp draw when I turn the headlights on or will blow fuses when I use the turn signals. The volt meter will go from 14+ volts to 12 as soon as the light switch goes on.
I've looked everywhere for exposed wiring or maybe some worn through insulation somewhere. At first I thought it was the wiring in my toy box trailer but, the motorhome I now tow with has no problem at all with that.
Up til now it's just been an PITA. Now, when I turn on the lights the EGT gauge goes nuts. The needle swings so rapidly it's just a blur. Turn the lights off and it's okay. This is driving me nuts. I've looked at all the easy and obvious places but cannot find the source of these problems.
Anyone got asny ideas/

onlychild

[BobND]

You have a bad ground between the engine and body, or the engine and the frame, etc..

[gmctd]

Try it with PARK lites only, headlites OFF

Try EMERGENCY flasher, only

[onlychild]

I had checked and cleaned the ground for the EGT and it's the same with the park lights.
I will go over and clean engine to frame/body grounds. It wouldn't take much to build a new cable for that. The flashers were mentioned and I wonder if I could have a faulty turn signal switch.
I have just re-located my FSD to the area in front of the left battery. I really gave those headlight wires a good going over looking for worn insulation.

onlychild

[Dvldog 8793]

Howdy
Sounds like a bad ground. I wouldn't waiste time cleaning them, if you take them off just replace them with new. might not hurt to add new grounds to the system. firewall should be connected to the engine and the frame, all body panels should be connected, frame should be connected to engine and charging system. the EGT gauge that I have works really good as a ground meter :D and had some of the same symptoms that you describe before I removed my engine and replaced all grnd straps. Hope this helps!
L8r
Conley

[gmctd]

Fault in PARK would seem to vindicate the headlite circuit, wouldn't you think?

TAILlite\trailer option circuit and\or front-clip PARK liting.

Circuits do not usually overload\short to ground, when bad ground connection is suspect.....

[patrick m.]

remove the elec center cover on the firewall, and inpect all of the fuse links. They are in a row, all are on studs with nuts as fasteners.

check that the connections are good at the nut. when the connections deteriorate, resitstance goes up, current goes down. (my word usage may not be exact, but you guys know what im saying :D )

you can look for voltage drop, feel the circuit get hot, use a socket to manipulate the nut and watch for a change in the symptoms. any of the above will let you know you have found the affected circuit.

[Dihrdbowti]

I have an issue along those same lines with my pyrometer as well except that it is every once in a while and only does it in when it's cold and I have head lights, turn signal and brakes applied. After it has warmed up it's fine.

[onlychild]

Thanks for the help. I'll try all of these suggestions and report back.

onlychild
DRR.com/nomad

[Jim P]

My pyrometer was going nuts but only when my turn signals were on. I found a broken ground wire that goes from the right battery to the inner fender.