Taillight Fuse blows when put in Drive

[awagz]

75 K10, when I put my truck in drive it always blows the taillight fuse which also results in my dash lights turning off. I replaced the fuse for a 30 amp and it still blows it. Where should I start my search for wire shorts?

 

[Raider L]

@awagz,
Well, you don't want to put a larger fuse in there, you could cause a fire or overheat the wiring. Man, the only thing I could think of is a possible short in the neutral safety switch, or the tail light switch? But think what does that have to do with shifting? You pull down on the shift lever, assuming you shift from the column. Is your shifter on the column? Or is the neutral safety switch on the transmission? You step on the brake when you shift, right? That might partially explain the tail lights going out when you shift to drive, but how do the panel lights go out to? Not unless the tail lights and the cluster feed are tied together in the fuse panel. My '74 C10 has separate fuses for tail lights and cluster feed fuses. Your tail light switch might be bad, but panel lights go out? You got me on that one.

 

[RetroC10Sport]

So it doesn't blow in park, reverse or neutral? Quite strange as Raider L said, because the taillights and dash lights are on two different circuits and neither of which are part of the neutral switch. I'd say that someone has monkeyed with the wiring in the dash somewhere and has it all balled up.

 

[Rusty Nail]

I'd look at the reverse bulbs.

 

[Rickf]

Maybe the issue is in the headlight switch? Could try to dis-connect the tail light harness from the firewall and see what happens.

 

[WebMonkey]

I'd look at the reverse bulbs.

^+1

when you're behind someone shifting from park to drive, the reverse lights 'blink' as the column switch passes over the connections.
could very well be a short in the reverse lights circuit somewhere.

good luck
'monkey