Under dash short circuit
 

Today I drove my 47 COE into town and in a parade. Afterwards I parked it. All was fine at that point.

When I got in to drive home it wouldn't start. Then I noticed the amp gauge was showing full discharge and a bit of smoke was coming from down by the ignition switch.

I figured out it was a wire going from the ignition switch to power the dash gauges and disconnected it. Drove home with no problems other than all of the gauges were dead.

At home I traced that wire and found it provides voltage to the oil pressure gauge and then on to the temperature and fuel gauges.

Disconnected the power lead to the temp. gauge as that was the easiest to get to and no short.

Put it back and disconnected the lead from the temp. gauge to the temp. sender and still no short.

Reconnected the wire from the temp. gauge to the temp. sender and no short.

At this point it was back to the original connections.

So I didn't really fix anything other than remove and re-install several wires. That doesn't leave me with a lot of confidence that the problem won't come back.

So, do I just use it and hope for the best? Or does anyone recognize these symptoms? Can a temperature or fuel gauge develop an internal short to ground?


Tom

Re: Under dash short circuit
 

Do you have a bare wire that is going to ground? What about a fuse - should have lost a fuse ?

Re: Under dash short circuit
 

Should be a circuit breaker if stock.

Re: Under dash short circuit
 

I put in a new wiring harness a few years ago and couldn't see bare wires in that area while tracking down the problem.

The wiring is pretty much stock. So it has circuit breakers for the headlights and tail lights but nothing else is protected.

I think I will add a fuse block under the dash to protect other circuits. Even with all new wiring in the truck, the gauges, or perhaps the various senders could be a problem.


Tom

Re: Under dash short circuit
 

Are you using the stock amp gauge where the wire loops through the gauge or an aftermarket amp gauge? If you are using an aftermarket gauge where the wires attach to two separate posts I would check a malfunction of the amp gauge.

Re: Under dash short circuit
 

It's the stock amp gauge with the wire looping through.

Tom

Re: Under dash short circuit
 

the ignition switch might have shorted out.