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79 TA: dash lights and tail lights fuse keeps blowing

2K views 6 replies 5 participants last post by  Gladis 
#1 ·
My friend suggested that it was corrosion in the tail lights, I cleaned them up but I am still getting the problem. It pretty much came out of no where and I can't drive at night pretty much. Anyone else ever have this problem?
 
#2 ·
Might have a wire chaffed and grounding out somewere causeing a short.Your front parking lights and taillights should be on the same circuit if I remember right.
I think with the fuse out and the light switch off you can test between the taillight/parking filiment wire(taillight bulbs have three wires grd,brake/signal lights and taillight/parking)to ground with an ohm meter,if you get 0 resistance you have a direct short somewere.
Someone else more knowledgable in the art of auto electric will chime in I;m sure.
 
#3 ·
I'm pretty sure that the taillights and the dash lights are on separate circuits.
They even have separate terminals on the HL switch.

Coming from nowhere----it might be a good idea to check the HL switch as this is the common starting point for both circuits.

Could be something in the switch has broken and fallen against the metal body and the buss inside the switch connecting the tail/dash lamps.

Check to see if you have 'park' lamps, I think they are on the same as the taillight circuit---------however, still a different terminal on the HL switch.

Bryan
 
#4 ·
I had this same problem on a 68 Olds 442. On that car, the dash and taillights ARE on the same fuse - and yes, they are fed by different terminals on the light switch on that car as well. Also on that fuse is the pigtail for the underhood light. Since I didn't have an underhood light, the pigtail was hanging loose and eventually rested against one of the header tubes, melting the insulation and blowing the fuse. Unfortunately for me, the wire would bounce around as I drove and naturally it was never grounded when I got home and tried to find the short. I finally spent a few hours tracing every wire in the wiring diagram that was on that circuit, which is how I finally found the problem. You need to get a factory service manual and wiring diagram and trace the wires.
 
#5 ·
Shorts, opens and fuses, Oh my!

In a car of this age, it could be MANY things. Agree with getting a meter and checking for a short to ground.

I'd pull the gauges and look behind and closely at the circuit board if you don't see something obvious such as a pinched wire at the tail lamp.

Changed anything lately?

Steve
 
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