I have a Chevy truck. It's not charging. The alternator works well in my Jeep, my Jeep one that works well in the Jeep doesn't in the tow rig. I know the field isn't being excited. If you don't know what I'm talking about please don't try to help:flipoff2: In cars the Gen. light burns out and makes the curcuit open, I don't have a generator light I have a guage. (I tore the dash apart so I'm sure) Any Ideas? I really want my tow rig back :(

Its the same as the light, if the guage has a loose connection or is bad, it will not charge. A cool trick to see if it is charging is to hold a wrench to the little circle on the back of the alternator. If it is magnetized and pulls the wrench against the circle, its charging.

Screwdriver works too. So If my stock guage isn't working it might be a problem? It's reading voltage correctly. Hmmm..... ????? So if I install an aftermarket guage will that do it? I could hook up an inline light but do I ground one side, and attach the other to the field side? No, I wire it from a positive to the field side I think? Though how would the light light? My crappy Chiltons wiring diagram doesn't show the circuit board.

I have an 89 chevy 3/4 ton with the 5.7 liter motor. The wire going into the alternator actually broke without the insulation breaking. I ended up replacing 1.5' of the wire from the connection back. It was a little strange but check yours with an ohm meter and see if its conducting current.

Duh I didn't check to see if it was getting any current through it. Damn multi meter's at the shop.

top.

OK can I put a bulb in line to use as the resistor? If so how do I wire it? Or will an aftermarket amp meter & or a volt meter work too?

you could connect a test light to the battery+, then to the field while the engine is running and not running, when off the test light should light, when running the test light should go out and the alt should charge.

Steve N, PM Yo Mammy Boy. He knows starters and alts inside and out.:)

Originally posted by Steve N
I have a Chevy truck. It's not charging. The alternator works well in my Jeep, my Jeep one that works well in the Jeep doesn't in the tow rig. I know the field isn't being excited. If you don't know what I'm talking about please don't try to help:flipoff2: In cars the Gen. light burns out and makes the curcuit open, I don't have a generator light I have a guage. (I tore the dash apart so I'm sure) Any Ideas? I really want my tow rig back :(

Steve what year Chevy truck Please

Adam,

'84 crewcab dually 454 auto loaded.

I gave up. I installed a one wire. It's not the right way to fix it but it works now.

Steve N


did you try to by pass the exiter contact from the gauge and draw 12 volts from another source? directly to the alternator?

and yes if you gauge is bad, you may have a short that would prevent power from comming back from the gauge.

Originally posted by Bigburlynakedguy
Its the same as the light, if the guage has a loose connection or is bad, it will not charge. A cool trick to see if it is charging is to hold a wrench to the little circle on the back of the alternator. If it is magnetized and pulls the wrench against the circle, its charging.

Why is my bearing magnetic even with the ignition off??

Does it only tell you if it's NOT charging (not magnetic)? :confused: