This is a wierd one. I have looked around and have not seen anything that covers this issue. Every time I use the left turn signal the fuse blows. I think that the cause if that I have a lot of stereo equipment in the rig. It did not do this until I installed my two Alpine amps, Kenwood head unit, and satillite radio. Before when I had just the stock stereo it worked fine. When I installed the Kenwood deck and amps it would blow the fuse when I used the left turn signal when the outside temp was above 80 degrees. After I installed my satillite tuner, it blows the fuse every time I use the left turn signal no matter what the temps are. The right turn signal does not seem to be effected at all. My question is do you think that this is inherient to this model and I would be wasting my $$ to have it replaced (since it cost approx $600-700) or is it something that I just have to live with? I've had the local toyota shop run all sorts of tests on the signal and they could not find anything wrong with the turn signal switch.

Any help would be appreciated.

Thanks,
McPerk

There is some important info missing here.

Things like...

What vehicle are we talking about here? Must be a Toyota, but model and year are useful if you expect us to remotely diagnose a problem without ever seeing the vehicle.

What fuse is blowing? The one for the turn signals, etc?

What circuit is the audio gear you added connected to? (Not a good idea if they're connected to the circuit powering the lights.) Did you do this yourself, and if so, could you provide a few details on what you did?

Does the fuse blow when the audio equip. is both on and off?

How much current does all this extra gear need? If you hooked a bunch of high-powered audio gear to any of the existing circuits, you shouldn't be surprised if you're blowing fuses.

I can say you'd certainly be wasting your money to have "this model" replaced even though I don't have a clue what you're talking about replacing. You need to understand the problem before going off half-cocked replacing stuff. Of course, if you want to toss stuff and buy something else, that helps keep the economy going.

If the Toyota shop couldn't find anything wrong with the switch didn't they try anything else? Were they trying it under the same conditions that cause it to blow when you use it? Did the fuse blow when they were testing it? Or does it blow only when you're driving down the road? If they can't figure out what is causing a fuse to blow that happens every time, they're incompetent and you should go somewhere else.

Check out the signature, it says 1997 LTD 4runner. That's the vehicle I'm talking about. The fuse that keeps blowing is the turn signal fuse. Amps are connected straight to the battery, not through the fuse box. The satillite tuner and stereo are connected through a wire harness from the factory wires. Don't know how much power it needs, since I don't have a volt meter, and am not about to go buy one just to diagnose this problem. Going to maybe replace the turn signal switch. The problem happens when you turn the ignition to the on position, since the turn signals only work then. It happens whether the stereo is turned on or off.

Just looking for a suggestion here, since I don't have the skills nessecary to fix this, nor do I plan on getting them.

McPerk

The extra info helps a lot.

Here is my long-winded 2 cents worth.

Since you've clarified the wiring, and the problem occurs even with it off, power consumption of the stereo gear shouldn't be an issue here. I thought it might be overloading the fuse if it was connected to the light circuit.

Your 97 should be close to my 2000. In that case, the only things on the turn signal fuse are the turn signal lights themselves, the indicator lights in the dash, and the relay that causes them to flash. The relay is used for both left and right lights, so I'd discount that as a problem.

First, I'd check in the areas where any stereo installation work was done to make sure no wires were inadvertently damaged (like cuts to the insulation, a wire being pinched between something) and that your stereo connections are really correct. (Make sure there are no connections that would be grounding the +12v line to either the turn signal lights themselves or the indicators in the dash). Since you said your new gear is connected either to the battery or to the harness for the factory gear miswiring to something unrelated like the turn signals doesn't seem real likely though. I suppose you could completely disconnect your connections to the battery and the other equipment from the factory harness and see what happens.

It sounds to me more like a short from +12V to ground in the wiring to the left turn signal lights somewhere downstream of the switch. It may be just a coincidence that it happened after your install. The temperature related aspect is sort of strange, although things expand and contract and get softer or harder as the temperature goes up and down that could have something to do with it. (A pinched wire might happen only when some part of the vehicle expands, eventually chafing the wire enough for it to always short out for example.)

I wouldn't replace the turn signal switch until I knew more. That sounds like an expensive shot in the dark.

The actual turn signal part of that switch on the column does nothing more than supply +12v to either the right or left turn signals and indicator lights. The hazard switch also turns on the turn signals (both sets at the same time). You could try turning that on and see what happens - if that fuse blows as well, it points even more strongly to something besides the turn signal switch. I suppose the short could be in one of the light housings, so you could look at the left side turn signal lights to see if something is loose or there is a lot of corrosion. I've never had a bulb short out, but I suppose its possible, so look at the bulbs as well.

If none of this works, I don't have any good suggestions for easy things to do. If it comes down to finding a short somewhere, without some special test equipment I think its a matter of trail and error to try to disconnect the wiring at the connectors that are available to narrow down where the problem is. I wouldn't try that without the wiring diagrams - tracing wires is just about impossible otherwise. You'd also need a meter to check resistances at the minimum.

I'm with Alan H on this, I think the stereo/amp setup probably does not have much of an impact on the situation, except that maybe something got cross wired during the installation.

I would certainly try the hazard switch, and see if that blows a fuse also, because that would effectivly rule out the turn signal switch as your problem.

If the right turn signal doesn't blow the fuse, it's probably not the blinker selenoid either, which would suggest that the problem lies somewhere between your blinker selenoid and the light fixture itself.

good luck
Erik <img src="/forums/images/graemlins/cheers.gif" alt="" />