Voltage regulator?

Back to Selahdoor, though, if there is one thing I hate, it's lying gauges. It sure is unnerving to operate any piece of machinery when it's trying to warn of impending failure.

I have a spare instrument cluster and was looking at it.... Noted it had two resistors on the circuit board. Can't help but think one of these is likely responible...they look like metal film resistors. I have not seen too many resistors drop resistance, though... Most I have seen seen fail increased resistance, which would be seen as an insufficient, not an overvoltage, reading. I will later tonight get a reading on those resistors and post what I read them to be.

I examined my spare cluster...

I probably botched my posting...I still haven't mastered this phone and my fat fingers.

The wires you see clipped to the meter go to a power supply set for 14 volts.

You can remove the meter assembly once you remove the clear plastic faceplate. It's held in place by seven T15 torx screws. Then remove the black bezel...it was held in place by the faceplate. The meter assembly was held in place by the electrical connector pins on the back.



See if your meter is still lying to you on the bench. There was no series resistor on my voltmeter.

Good luck.

Note my data is for the 1994 E350 van. The instrument cluster is off an earlier Ford truck.

Sorry about the lack of responses guys. I have been wondering if this was the sickness that was going to finally kill this old fart. Just got worse and worse. Started antibiotics today. Should be better in a few days. It's agonizing just making this one post.

Will be praying for you Bro

There's still no big hurry. I doubt that the truck will go very far without you.

Dragged my butt out there to try it again.

Probably shouldn't have. Felt like I'd lugged my entire house out there on my shoulders. This not being able to breathe thing, really kicks your butt!

Anyway, got the camera started recording. Turned the key.. Nada.

Oh yeah, it don't work with the batteries disconnected.

Get out, reconnect the batteries.

Start the recording... Turn the key... And for the life of me, I can't get it to do the same thing again.

I tried it several different ways. It just always returns to normal.

Well, it never actually started, either.

It's possible it only pegs the gauge when the engine is running. We'll see, once I get it started again.

I think it's losing prime. Which is strange because it never did, before I replaced the injectors and changed the IP timing.

I'm going to have to get the stuff to get the TEE and the electric fuel pump installed. Then I'll try again.

But if today is any indication, it may be a while before I have the strength again.


One last, the batteries didn't last very long, this time. Almost like they are not getting fully charged any more.

The volt guage is a side effect, because that go gp controller draws so much amperage when its heating. As all heaters do. You have a bad glow or 2. Hook a test light to positive battery terminal and touch the top of glow plugs with light. If it doesn't light up its bad.

I still think it's a bad connection between the alternator output and the battery.

The voltage regulator sees low battery and calls for higher alternator output.

But, thanks to the bad connection, the battery does not see it...but the voltmeter does.

I wish you Godspeed in your recovery. I had something similar earlier this year,. Worst thing I ever remember. Like you, I thought I was a goner. I gave away a lot of stuff because if the right people didn't get it, it would have gone to the landfill.

Going to work on this tomorrow.

Starting from the top of the thread.

franklin2 said:

He says the gauge pegs before he even starts the engine. So that would eliminate the regulator and the alternator both. I think there is something wrong with the gauge.

Click to expand...

As you will see in the video, the gauge reads normal, until the engine is started. It does jump around when the GP relay starts clicking. But it would stay in the normal range if I waited until the relay stopped clicking.

It then jumps to the top after the engine starts.

BeastMaster said:

Personally, i think this gremlin is in the instrument cluster...either the series current resistor to the voltage gauge, or a sneak current path around that resistor.

Click to expand...

BeastMaster said:

I probably botched my posting...I still haven't mastered this phone and my fat fingers.

The wires you see clipped to the meter go to a power supply set for 14 volts.

You can remove the meter assembly once you remove the clear plastic faceplate. It's held in place by seven T15 torx screws. Then remove the black bezel...it was held in place by the faceplate. The meter assembly was held in place by the electrical connector pins on the back.

See if your meter is still lying to you on the bench. There was no series resistor on my voltmeter.

Click to expand...

I do think it is in the alternator/regulator.

I'll know more by the end of the day.

For one, I am going to clean up the connections between the alternator and battery, and the alternator and voltage regulator and see if that makes any difference.

crr31c said:

The volt guage is a side effect, because that go gp controller draws so much amperage when its heating. As all heaters do. You have a bad glow or 2. Hook a test light to positive battery terminal and touch the top of glow plugs with light. If it doesn't light up its bad.

Click to expand...

I have all new glow plugs. At some point, though, I am going to replace the entire harness with one that Chillman88 sent me. Going to wire that directly to a starter solenoid, instead, and use a momentary toggle for the switch. This is to test the GPs, with the standard relay stuff all out of the way.



Now, for some test results...

With the batteries fully charged... (They started the engine, no problem.)


Negative cables off. From one negative terminal to the other... .04v


Battery voltage:

12.92 volts, not running. (This changed to 13.35 volts, not running... After the engine had been run for about 5 to 10 minutes.)

15.61 volts, running.



Still to do, today.

Try starting with just one battery. Then with just the other battery. I'm thinking it will be the same for both, but worth doing, just because.

Clean up all the connections between the alt and anything else... Including the alt ground.

Any other suggestions?



I think I'll also try to get some pics worth looking at... Of the alternator, and regulator.

Then go get pics of the alt in my other truck. I think that one is an upgrade. The kid said something about an alternator from a Cadillac or something, and no regulator in the system.

What I am going to want/need, is recommendations on whether to swap that setup into here. And what I am going to have to do about the wiring system in here, to get that done without messing anything else up.

Selahdoor said:

15.61 volts, running.

Click to expand...

That's on the high side. I believe that you want around 13.5 to 14.5 volts while running.

Selahdoor said:

As you will see in the video, the gauge reads normal, until the engine is started. It does jump around when the GP relay starts clicking. But it would stay in the normal range if I waited until the relay stopped clicking.

It then jumps to the top after the engine starts.

Click to expand...

Mine does the exact same thing, and expected. That glow plug relay is switching a heavy electrical load, 200 amp or so, on and off. You expect to see that on your battery buss. Get used to how much it perturbs a good set of batteries. Now you are more prepared to know if your batteries are deteriorating or your glow plugs are failing by watching the voltmeter during startup.

Once the engine kicks in, the alternator should come online and boost the battery buss to 14 volts or so. I have a 130 Amp alt on my van...which barely covers air conditioning and lights at idle. Otherwise more than plenty.

I find this easy to see if I am shining my lights on my garage door at night...does goosing the engine brighten the lights?

If it does, I'm not charging at idle, and, worse, maybe discharging. It takes a helluva lot to start these beasts, and I want to put my battery to bed with a full charge in it.

I think 15.6 volts is a tad high. If you keep ramming current into a lead acid cell, you start electrolyzing the water in the cell, and start boiling off a mixture of hydrogen and oxygen gas. It's not good news if an electrical spark is nearby, even worse if a pair of eyes is within eruption distance. Until you know for sure you are not overcharging, please have extra caution around the battery.

15.6 volts should give you quite bright headlights.

I kinda suspect your meter. I'd get a second opinion from another meter.

IDIBRONCO said:

That's on the high side. I believe that you want around 13.5 to 14.5 volts while running.

Click to expand...

BeastMaster said:

Mine does the exact same thing, and expected. That glow plug relay is switching a heavy electrical load, 200 amp or so, on and off. You expect to see that on your battery buss. Get used to how much it perturbs a good set of batteries. Now you are more prepared to know if your batteries are deteriorating or your glow plugs are failing by watching the voltmeter during startup.

Once the engine kicks in, the alternator should come online and boost the battery buss to 14 volts or so. I have a 130 Amp alt on my van...which barely covers air conditioning and lights at idle. Otherwise more than plenty.

I find this easy to see if I am shining my lights on my garage door at night...does goosing the engine brighten the lights?

If it does, I'm not charging at idle, and, worse, maybe discharging. It takes a helluva lot to start these beasts, and I want to put my battery to bed with a full charge in it.

I think 15.6 volts is a tad high. If you keep ramming current into a lead acid cell, you start electrolyzing the water in the cell, and start boiling off a mixture of hydrogen and oxygen gas. It's not good news if an electrical spark is nearby, even worse if a pair of eyes is within eruption distance. Until you know for sure you are not overcharging, please have extra caution around the battery.

15.6 volts should give you quite bright headlights.

I kinda suspect your meter. I'd get a second opinion from another meter.

Click to expand...

Yep. Not concerned about the GP relay causing the jumping needle on the gauge. That was easy enough to figure out as soon as I saw it.

Problem is with it going to 18v and staying there.

Technically, I have already gotten another opinion from a separate meter. My voltmeter. It is charging at 15.6v. That is too much.


I put a new ground wire, (Made from an old jumper cable), from the base of the alternator directly to the ground cable of the battery.

Took apart all the connections at the alternator, cleaned them up, added silicone grease, tightened everything back up... Still the same results.



Headed in for a dentist appointment on wednesday. So, tomorrow I am going to take the alternator out. Then I'll take it in on wednesday and have everything tested.

I suspect I killed the regulator when I jump started it from the car.

BTW: Both batteries read the same.

I think 0.4v between the negative posts is fine.

Did try starting it on just one battery, and then just the other.

It was slightly easier to start, with the passenger side battery, than it was with the driver's side battery. But something tells me that is normal.