Volts light flicker

[wlaukaitis]

Hi Folks,

OK, I just the car back together after a few gasket replacements (upper plenum, valve covers, throttle body, vacuum block) and a new Cat. I also remove the trans inspection cover to have a gander at my trans/oil waterfall leaks. I noticed a heat shield that was rubbing some wires, I think it was the starter wires so I bent it out of the way a bit.

I have a somewhat flickering Volts light. Initially it would be off at idle and get brighter as the RPM's increased. I shut it down for about 2 hours and went back out to start it. Still off at idle but as the rpm's increased it would flicker.

I could not get a good reading from - to alt +, I have to clean a good ground and Alt +.

Battery voltage is 11.6 even with the car running, as RPM increases I could hit about 12.5 (maybe at 2500 or so)

I'm thinking Alternator, I guess it decided to crap out on me. I saw a post where you take a VOM and go from Batt + to Alt + (the terminal) is this true?

 

[Shane]

Here's a thought. Get a long wire and a resistor. Connect the wire to the resistor and the other end to + on the battery. Splice this into the Brown wire that goes into the Alternator (Sense voltage).

Now check system voltage on your VOM or Scanmaster. If it reads ~13VDC, you have an small open in your sense line. Let me know, I had to fab up a circuit on my last GN to make this work because I was too damned lazy to open up the dash and troubleshoot. I can guide you through it.

 

[wlaukaitis]

What kind/size of resistor?

 

[Shane]

Try about a 1 Watt 1KOhm Resistor.

 

[turbo nasty]

The battery voltage is too low at idle it should be higher than 11.6.

Here is somewhere to look the wire(red) that goes from the back of the alt to the starter check both ends.
I had an erratic volt light and the wire had came out of the ring terminal at the starter....goofball who had the car before me did not crimp it down right....replaced terminal and walla.

 

[wlaukaitis]

Since the post, the light only comes on when the key is on, that's it.

I had the dash apart to lube the speedo, I also cleaned all the contacts for the lights and I checked them with my voltmeter on "beep" mode to make sure they all worked -or- passed continuity through the bulb.

Most of the problems were due to poor contact in the BULB SOCKET, not bulb socket to PCB contact. Now most of the gauge cluster light work.

Well, I gave the batt a good charge and started it (cold) and was
getting 13.6 - 14.0 at idle out of the alternator. Since the idle was a smidge high becasue it was cold, I think the voltage was good. I am going to try to get my buddies snap-on charging system tester on Fri. I will check the wires when I put the trans inspection cover back on.

This all started when I replaced the valve cover gaskets, I had to "convince" the wiring harness to let me get the valve cover off, although not too harshly.

we'll see what happens!

Thanks for all the help.
Bill