voltage reg or alternator

drahthaar1 · 02-01-2005, 07:18 PM

To day the 96 passport five speed was acting up. you could watch the voltage on the gauge drop to everytime you hit the gas. If you braked really hard the stereo would stop. I have been noticing the blower fan while running the heater change speeds, but today it was very bad. When I would hit the brakes it would drop the voltage from 14 to 9. The gas would go from 14 to 12 and turn on other electric would bring it down as wiell. I tested the dome light to see if it flickered and it did.

Then I hit the brakes hard and abs light and fourwheel drive light started flashing and the elngine just bucked. I pushed in the clutch and no success. I placed it in second gear and flored it the was a car behind me. There still was no luck. The whole time the four wheel drive and abs light are flashing. Then it can out of it ran normal with the voltage drops still occuring.

I think that it is the voltage regulator. I just whated someone elses imput.

Thank
Joe

Slade901 · 02-02-2005, 06:51 AM

You can have your alternator removed and tested at Autozone for FREE since the the voltage regulator is on the alternator itself. However, check all you wirings, especially the battery terminal cables and make sure they are tight. Don't forget to check for the belt and make it is still tight to spin the alternator.

drahthaar1 · 02-02-2005, 04:05 PM

I went to Shucks auto and the did a electrical test on the witht eh alternator still on the vehicle.

To begin with he said that I had a bad battery. I replaced it. he said tha alternator was fine and it wasn't dropping voltage when I did the thing that made it drop the voltage meeter was dropping.

I noticed that driving it still is doing that. If I turn on the blower it drops to 12 and goes back up. Anytime that I hit the gas it drops to 12 until I let off. I tested this as well outside on the battery with a voltage meter. I put the volt meter on and used the cable to accelerate. It did it.

Then I noticed that if the head lights are on. It doesn't do it. It states at a constant voltage.

Any Suggestions

Thanks
Joe

Canucklehead · 02-02-2005, 04:17 PM

As odd as this may seem, it is completely normal.

From page 2-8 of the 1997 (1996 as well?) Rodeo Owner's Manual:
"When the accelerator pedal is pressed, when driving or with the engine idling, the voltmeter will drop into the low voltage range. This results from a changeover in alternator voltage control designed for fuel economy improvement. However, the voltmeter needle will not drop if the head lights are turned on or if the engine coolant temperature remains low."

amigo-2k · 02-02-2005, 04:19 PM

sounds like the alt is pooping out under engine load, but is fine at idle.

Canucklehead · 02-02-2005, 04:26 PM

Quote:

Originally Posted by amigo-2k

sounds like the alt is pooping out under engine load, but is fine at idle.

The bit about voltage not dropping when the lights are on is the key. "96 and '97 Rodeos (not sure about 2nd Gen) have an input to the VR from the ECM which I'm pretty sure is what tells the alternator that the headlights are on, therefore telling it not to change alternator voltage control to "fuel economy mode".

drahthaar1 · 02-02-2005, 06:01 PM

Thanks I don't have an owners manual so I thought that it seem fishy

Thanks
Joe

2eyefishclaw · 02-03-2005, 12:21 AM

it is normal for them to do this

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