dc2x4drvr

I replaced the fuse and it blew as soon as I turned the key to the on position. Where should I start troubleshooting..turn signal switch, neutral safety switch??

jaunty75

How about the turn signal wiring itself? There could be a short somewhere in the line. Have you checked the wiring at the lights themselves to be sure that something isn't pinched somewhere?


I had a very similar problem with the taillights in my Custom Cruiser, but it wasn't turning the key on that did it, it was just pulling out the headlight switch. The moment I did so, the taillight fuse would blow. Turned out to be a bad ground in one of the side-marker lights in the rear of the car.


One piece of testing equipment that turned out to be very valuable was one of those short circuit testers. These go in in place of the fuse and have a very fast acting circuit breaker which resets the instant the short occurs and does this many times a second. You then have a second piece, more of current detector, that you hold over the wiring which senses the rapidly oscillating current flow in the wire. As long as you are between the power source and the short, the sensor needle oscillates. When you move the sensor past the point of the short, the needle stops moving as there is no current at all in that part of the wire. The beauty of it is that you do not need to make an electrical connection to the wiring for this to work. It senses the oscillating magnetic field that occurs around a varying electric current.

Because my problem turned out to be at the very end of the wiring, in the end, this tool didn't really help me pinpoint the short. But where it DID help was in that it told me where the short was NOT, which was really just about as valuable.

olds425

I have seen the bulbs rust in thier sockets and cause this. I would check the bulbs and make sure they are OK.

Lady72nRob71

Alligator clip an old headlight across the fuse holder. If the bulb comes on, then the short is there. If it does not, then the short is gone. Saves $ in fuses...

That fuse feeds the turn signals, back up lights, and the TCS solenoid at the front of the engine.
I assume the TS lever is off (middle) and shifter is in park.

First look at the TCS connector and make sure it is not up against something metal, esp if the TCS was removed or bypassed. Check engine harness for obvious damage. Unplug the TCS to rule it out if need be.

Second, check for any wiring hacks under the dash a PO may have done. I cannot believe what people will do to get tunes in their car...
Check green wires to neutral switch.

If that all okay, then pull the TS flasher. If the short stops, the TS circuit is shorted, most likely in the switch if the lever is off.
If the TS is either L or R, then check the bulbs for correct type, rust, and correct installation.

This will get us started...

jaunty75

It may save money in fuses, but it assumes you have an old headlight.

This is also dangerous because the headlight is not a fuse, and if the current is allowed to pass through the headlight and on to the rest of the circuit, wherever the short actually is could get burned or a fire could be started.

He doesn't need the headlight lighting up to tell him the short is there. The fact that the fuse blows the minute the key is turned on tells him that.

For about $3 or $4, he can go to a place like NAPA and buy a circuit-breaker of the same amperage as the fuse that keeps blowing, and plug that in where the fuse goes. Then he still has the protection afforded by the circuit breaker while hunting for the problem, and he's not continually blowing fuses. The other beauty of this is that these circuit-breakers are self-resetting, so the minute he finds and fixes the short, the lights that should be coming on will do so.

dc2x4drvr

Thanks for the help, I think Rob nailed my problem...I just had my console out while replacing my clutch, and I keep the TCS wire/connector underneath it since I don't have the solenoid installed. I'll bet when I shoved the connector under the console it struck metal..
I'll let you know.

Lady72nRob71

True, the headlight is not a fuse (not supposed to be), but it is used to limit the current to 3-5A or less (whatever the normal draw of the bulb) during troubleshooting.
You would not keep it clipped in there all the time, too. Connect it - it lights up, okay, acknowledge short is there, disconnect it, continue troubleshooting / isolating circuits, repeat... Good way to narrow down a problem quickly using parts that many of us have laying around the garage.

This is kind of like setting a current limit on a benchtop power supply - limit current to prevent damage and fire, while letting the short be there to troubleshoot. We do it in the lab on a routine basis.

The current limit needs to higher than the typical draw of the circuit you are working on.
A smaller bulb (1156 backup light) could be used in small circuits, such as this one. The headlight works better when working on bigger circuits like the A/C blower and light circuit.

A circuit breaker could actually be more dangerous because a very high current surge would be made with each break, which is usually well above its rated continuous rating.
If you wish to use a breaker, use one that is about half of the fuse rating of the circuit you are working on. As mentioned in another thread, the fuses chosen are a bit more than they really should be.

Hope this did not get too confusing....

Hope it is an easy fix...

dc2x4drvr

Yup, the connector was up against the console bracket, I taped the connector so I won't have to worry about it shorting my wiring again.
Thanks Rob!

Lady72nRob71

No prob!
Glad it is fixed...