Generator/Computer

I had a generator go bad in my 99 1500. The last time I drove it, the entire system went haywire. The A/C quit, the speedometer was erratic, the trans shifted erraticly and slipped, the engine missed, the antilock light on the dash lit. I might have damaged the computer with a bad generator. The voltage was all over the place.

I would buy a rebuilt alternator install it and charge the battery. If everything works properly you should be in good shape. Sometimes when they go bad they put out AC power and the system won't work properly. This doesn't happen often but can.

I installed a NEW alternator, belt tensioner, and idler. The battery is close to full charge. When I test drove it afterward, The A/C worked, but the rest is the same. Antilock light lit, engine missing, Trans shifts off, etc.

Check all fuses and fuseable links.

I checked all fuses in box under hood. All were good. Are there any more outside of box?

I think their is another one under the left side of the instrument panel.
http://www.alldata.com/ sells a years service for around $25.00 they have good wiring diagrams.
Check grounds rear of engine compt. right side of cowl panel. Lower left cowl panel.VSS pnk/org Left radiator support. This is for a 5.4L engine.

Mine is the 4.3L, but it shouldn't be too different. I have ordered the factory service manual from a dealer on Ebay. We'll see how that works out.

I have recieved the factory manuals. 4 large books. Talk about information overload. I'm going to be busy for a while. All fuses I can find check good.

After sitting for a few weeks, the truck operates normally. Either I have a bad or intermittent ground, or moisture has gotten into the ECM. I need to find as many ground points as I can. Where is the ground point for the ECM?

I looked at a 1997 4.3 and one ground is left rear of block. Right side of dash above blower motor. Thermostat housing,right side of frame rail. Left rear of block by knock sensor.

After sitting for a few weeks, the truck operates normally. Either I have a bad or intermittent ground, or moisture has gotten into the ECM. I need to find as many ground points as I can. Where is the ground point for the ECM?


The factory repair manuals should show all grounds.
For checking grounds get a good volt ohm meter and run a voltage drop test on them.

I bought a preprogrammed ECM from an Ebay dealer. The unit came with instructions for "learning" a pass code form other components. Seems strange to me.

I bought a preprogrammed ECM from an Ebay dealer. The unit came with instructions for "learning" a pass code form other components. Seems strange to me.

Start a New Thread /Post on your problem.