Because so many systems are involved I would get set up to monitor system voltage during an event. Use either a DVM wired to the battery or main fuse/relay block or one of those cigarette lighter plug in digital voltmeters and watch your system voltage both during normal and faulty operation.

Also, do your interior lights have a light flicker when the truck is running?


George

 

Thank You for all the help guys, sorry for giving the ghost! I was on a vacation in Florida & left the Jimmy home.


My Thoughts exactly!

It has been in the back of my mind! Though to be quite honest I haven't checked into much as of late. It appears to be working, giving around 14V but, I haven't looked into it more than that. It was replaced close to 10 years ago. I have checked the harness to it & the positive cable both showing no corrosion.

I will definitely look into that tomorrow! As you said I have just checked the box & cleaned up the ground on there. So far just my girlfriend gives me grief about the truck & trying to get me to get another car, lets hope the horn doesnt start going off or she'll really get her wish, hahaha.

I'm trying my best not to give up!

I will definitely try to monitor voltage during an event but to be honest it comes on so fast & it momentary. Thankfully the engine does not get affected by the condition & she doesn't skip a beat.

Yes, the lights flicker when its running but only when the truck is at idle. If the engine is cold, the electronics & lights do not flicker & I have no electrical problems. But after 20-30 minutes or so the electrical gremlins show their face.

Thanks Again Everyone, I really appreciate the help!

 

That story does not sound like a short and easy one...As far as I remember disassembling the dashboard is a pain in .... for every car. Not to mention You may find nothing underneath :P Anyway, that does not look like a very difficult, but time consuming repair.
I'd like to add my 3 cents in regards to a voltage monitoring:

• get a wiring diagram
• make the list of a known symptoms
• locate the devices on a diagram
• bear in mind, the ground wire splits to a different power receivers, so by analyzing Your wiring diagram try finding the first ground wire, that match only the receivers with symptoms

The point is, that if You hook up with a DVM device to a good working (well grounded) circuit part You'd hardly find anything.

It's not the battery nor an alternator, as You'd have problems cranking Your engine (hell yeah, there's a huge current consumption).

GL with finding Your faulty wire.

 

I initially missed the part where your engine never misses a beat. Please list all functions that have malfunctioned and I'll give you sone ideas where to start.

George

 

Good News Folks!

Although I can't explain much, because I'm not exactly sure what fixed it. I gave it a week thus far to be a bit more sure that it's fixed.

I went through the engine bay again checking grounds & other wiring, everything checked out. I went underneath the driver's kick panel & took apart connectors to the BCM, they looked good but I blew some compressed air across them & put em back together. I ran some 12 gauge wire from the underhood light ground on the firewall & routed it through the fender & through the rubber bellow for the driver's side door. I routed it to the set of grounds on the firewall near the instrument cluster. I buttoned everything up & she hasn't skipped a beat since. I don't know what exactly fixed it to be honest. Lets just hope the problem is solved! At least it happened right when I was test driving Tahoes, hahahaha. The only strange thing, is now the dimmer does not dim the overhead console display or the radio display. I could really care less but, I found it strange.

Thanks Again Guys!!

 

I have been reading on this forum to.
I have a 1996 GMC JIMMY SLS 4WD 2door. With the same issue of the alternator getting hot. This is a new alternator from Summit Racing, the OE style ACdelco. Why I replaced the old alternator was the voltage regulator went bad. voltage went up to 15.6 -15.8.
I have went through the dash all wiring. One wire at at a time. went through the wiring on the interior against firewall by the steering wheel to passenger side. I did have to fix a few wires that a mouse chewed the insulation on wires at the heater core area. I have also took out the seats and carpet and traced the wires inside from taillights to the dash. All was A ok. Alternator still get's hot. Any suggestions ?? I do know it is a ground issue.
Engine runs really well. Mileage on vehicle is 123,456.
New battery installed, new distributor, new spark plugs and wires, new ignition control module and heat sink, new fuel pump, new fuel lines, changed from poppet style injection to the new style injection. new upper gaskets on engine. All new brake line's, caliper's, wheel cylinder's. On interior vehicle new multifunction switch, new ignition switch, new brake light switch. Have replaced on front of vehicle, new ball joints with A arms, new cv axles on both sides, new brake dust cover with ABS sensor, new shocks. I did misplace the brake light switch retainer. IF ANYONE knows where to get a brake light switch retainer PLEASE share info.

Mike

 

Why do you believe that you have a ground problem? How hot does the alternator get?


George

 

Alternator get's hot enough to burn ya hand. Still looking for the issue that is causing this. will know more later in this day. Still could be in the wiring harness on diver's side under vehicle on frame in the wire loom.

Thanks for replying.

Mike

 

Alternators can get up to 200F with some maximum specs higher than that. That is too hot to touch. In the boating world where alternator and regulators are adjustable with temp sensors most guys set a temp limit of around 190F. They get hotter when their output is higher like with a lot of loads, including a depleted or defective battery. Excessive temps can also be caused by bearings, bad diodes, corroded connections, belts, etc.

A bad alternator ground is easy enough to check. Measure the voltage between the battery ground post and the alternator case with a bunch of loads on and make sure it’s not above 0.2v. Ground problems elsewhere will Likely reduce alternator load and temps.

What is your charging voltage with the engine running and if you have a clamp ammeter what is the alternator current output?

If you have an alternator overheating problem the issue is not likely to be under your dash or frame.

George

 

I got my blazer warmed up in the driveway at idle for about 20 minutes. Outside temp was around 90F. My alternator case temp was 185F. FYI.

George