bad300sport

So I installed a generic sun pro tach in my '88 Sport Coupe (carb'd 350) 'cause the factory tach doesnt work. I get everything hooked up and everything goin fine till I turn on the lights to make sure the tach light is working and POP! Taillights and gauges lights are out. Replace the fuse POP! Checked the tach wiring, replaced fuse POP! Found a better ground for the tach, replaced fuse POP! Removed the tach, replaced fuse POP! What gives!! I'm guessing a short but from what?? I completely unhooked the tach and it's still popping fuses, I check the wiring and found no irregularites (burnt, melted wires etc). It started out only when I turn the lights on, now even if the lights are off and the ign is off, it's still poppin them. Seriously this is a pain, I cant drive the car just bc it keeps poppin fuses and I have no dash/tail lights!!!

Btw previous owner had a 30A fuse in place (marked 20A), at first I replaced it with the correct 20A, then a 25A (actually a couple of those) then a 30A, finally I got tired of messing with it and threw in a 40A and it popped it too, almost instantly.

DENN_SHAH

iTrader: (1)

it could just be a coincidence that it started happening when you installed the tach.
because its blowing the fuse with the lights off, possibly a problem with the headlight switch. unplugging the switch should stop the fuse from blowing.
if it does, the next thing i would do is pull all the park light bulbs, plug the light switch back in and try it again with a 20 amp fuse.
don't forget pull the front and side parking lights too before trying it again.

bad300sport

Thanks I'll give it a go next time I got some time on my hands

bad300sport

So it was finally decent enough outside I was able to remove and unhook all the bulbs/lights. It's still poppin fuses!!!

You guys think one of those plastic quick splice clips could be causing the short???

Sick92

Firstly, NEVER NEVER NEVER NEVER NEVER use a BIGGER FUSE. You'll chance burning up your wiring / starting a fire.

Those quick splice clips are terrible. I've seen them used, but it cuts much needed wire and decreases the diamater = less max amperage.

Check for anything you may have modified, or "moved" or "jerked" while installing this. The slightest exposed wire could make this happen...

bad300sport

Ya I ditched the plastic clips, did notice some damage to the wire(s). I also dropped the fuse block just to see if I knocked anything loose. Did find out the harness coming from the steering column (the larger one, about 10 wires that attaches to side of column) was actually broken in two. I found that out b/c after I popped the clip that holds them together and went to pull it apart, only half of it disconnected haha.

So I'm gonna set about repairing the damage wires I've found (previous tach install or maybe previous owner just checkin for continuity by cutting into the wires??) as well as the broken harness clip......figures I just sold an older Jeep (GM Style) steering column with perfectly good harness.

bad300sport

So I finally managed to repair the damaged wires and it's still popping the fuse!!! When I first hooked the tach up I accidentally hooked the light for the tach into the hazard flasher (brown wire) then realized my mistake and hooked it into the brake light (white wire).....hey cut me some slack it was dark and I'm not accustomed to Chevies haha. Anyway, I straightened all that out and brake lights and hazards work as they should. Is it possible it could just be the headlight switch???