Electrical Problem.

[Jim Wright]

On Jan 7, 2014, at 4:46 PM, Eric Hope wrote:

> Seeing that I have been a member of this list for almost as long as I've had my SE-R (going on 21yrs!), I know I can get a better clue to my problem knowing who is on here. Put us all together and we've been there/done that!
> 
> So here's the deal. My 91 started having a weird electrical problem. The alternator will not start charging unless I give a quick hit to the throttle to 3k rpm and then it starts working like normal. That sounds like the diode in the alternator has gone bad, so what. 
> 
> Here's the weird thing, at about the same time I started having alternator issues the RPM gauge, A/C blower motor, fuel gauge, turning signals as well as all the ignition lights stopped working. I checked the ignition switch, grounds and fuses and they all look good but won't work when the alternator is charging at 14.1V. This car is 100% stock except for the aftermarket alarm which was installed long, long ago. I know electrical problems can be a pain, but with all those instruments going out at the same time means its one problem, I just can't find it. I plan on changing the alternator this weekend but doubt that will fix this issue.


Hey Eric.  First of all, I have no clue on this one, I've never heard of anything like it before.  A few questions…

You say the alternator won't charge until you blip the throttle past 3k.  How are you determining this?  Do you have a voltmeter reading the battery voltage, and are seeing ~12v until you blip it, then you're seeing about 14.4v?   Does the alternator continue to charge once it starts, or is it only charging when above 3k?

You original message said 'ignition lights stopped working', do you mean instrument lights?  Sounds like it from all else you described.

You said the gauges/blower/turn signals don't work when the alternator is charging, do they work normally when it isn't charging?  What about with the engine off?


I don't have an electrical diagram handy, but my gut is telling me a relay may be at fault, or that something is shorted out.  Just for fun, try disconnecting the wiring from the alternator, and see if the problems persist after 3k.