Got a short somewhere ...

[Duffman]

I am having challenges with my 70 Z and blowiing out my fuse for my gauges and marker lights. I started having this problem a few weeks ago . When I change the fuse, start the car and let it idle, no problem. When I rev up the engine, the fuse usually blows and none of my gauges works (other than speedo, of course), and my marker lights are out. Not being much of an electical genius, any sure-fire steps I should take to find the problem?

Thanks,

Stephen

[Duffman]

Sorry, the marker lights don't go out, just the gauges ...

[peng155]

I wanna say check the output voltage on your voltage regulator.... But for some reason I don't think this maybe the problem....

If your blowing a fuse it usually means that something is drawing more current in your circuit than the rating of the fuse.... But if it only happens when you rev the engine the only thing that changes is the engine RPM, and the alternator connected to teh engine via the alternator belt....

[Mr Camouflage]

Step 1. Take it to an auto electrician.

Step 2. Pay the bill.

Problem solved.

Might be the voltage regulator, not regulating the voltage.

If you have a multi meter, check the voltage at the battery with the engine running at idle. then get someone to rev it to 3000 and check it again.

I dont know what the voltage should be, id be guessing if i said, so i'll leave it up to someone that knows, but there shouldn't be much of a difference between the two speeds. If its any more than 15 volts, i'd be worried.

If you have the original VR, I belive they can be serviced, but you'd have to do it yourself, VR's these days are electronic, and an auto electrician would replace it with the electronic type.

[Duffman]

I replaced my alternator with an upgraded, higher output model (60 amps), during the problem. But I am having the problem with the blown fuse after I did it, as well. The new alternator has the built in voltage regulator.

Any other thoughts?

[Arne]

Well, in that case I'd lean toward a defective or improperly wired gauge. Since it blows the fuse when you rev it, I'd probably start with the tach. The only other likely candidate is the ammeter, but I don't think it is wired in such a way that it could blow the fuse. None of the other gauges fluctuate directly with the revs.

[Duffman]

Thanks, Arne. By the way used your harness with my alternator, works great! Now if I can figure out my fuse problem, I will be set!

[Duffman]

I was trying to think of anything I have done that would cause this problem. The only thing that comes to mind is this started happening around the time I put in a Honda fan to increase air flow. However, the fan is on a separate circuit/fuse, which doesn't blow. Could I have done something to cause a short when I installed the fan? I have checked and don't visibly see any bare wires or anything that could short.