Voltage High

Reply Subscribe

Thread Tools

Search this Thread

Sep 12, 2007 | 09:33 AM

qman

Thread Starter

Cargo Master

Joined: Sep 2004

Posts: 2,691

Likes: 6

Voltage High

I replaced the voltage regulator on my 92 (300 I6 5 speed). With the old one in there, the voltage would intermittently flutter around center on the dash voltmeter. Sometimes it would flutter, and sometimes not. When not fluttering, all was good. When fluttering, I would sometimes have problems with electric things turning off and on. Examples of this are the radio turns off for a second if I hit the brake or turn on the turn signal. Sometimes if I hit the brake pedal the engine will cycle on/off. There was no pattern to any of it. It was completely intermittent. I put on a new voltage regulator and I have the same intermittent problems with things cycling off/on. The difference is that when the truck is in this bad state, the voltage is almost pegged at the high end (18 volts). It doesn't flutter anymore, it just reads high. On some evenings if I have the radio, heater motor, and headlights on, and I turn up the volume on the radio, the voltage will drop way down and the heater motor slows, the headlights dim, and the engine almost dies. If I turn down the volume, everything picks back up.

Anyone have any ideas? I'm completely stumped. Why would a voltage regulator not regulate?

Sep 12, 2007 | 09:56 AM

kaug23

Freshman User

Joined: Aug 2007

Posts: 41

Likes: 0

Check your ground connection from the engine to the body of the truck. A bad ground will cause the lights/radio/gauges to do funny things. Have you actually checked the voltage with a digital meter? It may be the gauge on the truck is acting funny because of the bad ground, but you need to check it anyway. If it really is 18 volts you will be burning up the battery and probably the computer in your truck.

Sep 12, 2007 | 09:57 AM

jroehl

Post Fiend

Joined: Apr 2004

Posts: 6,473

Likes: 4

From: Lafayette, IN

Sounds like you have a loose connection somewhere or maybe a bad ignition switch, or your alternator could be bad.

Jason

Sep 12, 2007 | 10:02 AM

qman

Thread Starter

Cargo Master

Joined: Sep 2004

Posts: 2,691

Likes: 6

Thanks for the responses. I did check the voltage at the battery. It is the same there as on the dash. I have checked the ground from the engine to the body and from the battery to the body.

The ingntion switch is new.

Why would a loose connection make the voltage regulator not regulate?

How could a bad alternator cause this?

Sep 12, 2007 | 10:26 AM

rattosh51

Mountain Pass

Joined: Apr 2007

Posts: 237

Likes: 2

From: St. Paul, MN

Bad grounding can cause all kinds of weird problems because the circuit gets isolated. If the voltage is that high at the battery, then I would suspect the alternator. Take it to a shop, or parts place...they can check it on the vehicle.

Sep 12, 2007 | 10:37 AM

netscaner

Elder User

Joined: May 2007

Posts: 754

Likes: 1

From: Solon, Ohio

The regulator can only regulate the voltage at the exact points that it is connected at.

If you have bad grounds or bad connections elsewhere then the regulator has no way of sensing this.