6.9 idi voltage regulator location

[Stu Bailey]

Hey ya'll. First post, new to the forum, new to the diesel world. Bought a super clean 86 6.9 last year in October. Bought her out of Oregon and had her shipped to Alaska, then drove her all the way to Los Angeles and then to New Jersey with no problems. Having a hard time with keeping her juiced up now. Batteries were from 2009 so I bought new ones, those drained so I pulled alternator and had it tested, failed twice at two different shops. Bought a new one and installed it. Just wandering if anyone could tell me about the voltage regulator and it's supposed location. Also if anyone has information on belt tension from the double pulleys on the alternator. Did you crank em tight? Loose? Or the normal 1/4" give. Thanks again. The truck has 152 000 miles on it
86 F250 6.9idi
152,000 miles
New Jersey

 

[Stu Bailey]

Just went out to the truck and batteries are completely dead after being at full charge, sitting at 2 volts. When the alternator is hooked up and the batteries are as well, there is what appears to be a 3.5 amp draw from somewhere during draw test. I pulled all fuses and nothing showed.

 

[Thewespaul]

If you follow the wires from the alt you should come to the reg. Should be in the passenger fender area if it hasn’t been moved. With the engine cold is the new alt warm to the touch?

 

[Stu Bailey]

Can't start the truck till I recharge the batteries since they are dead. The alternator is brand new though, only have 30 minutes run time on it. Found the regulator easily, just wandering now if there is anything that can be draining the batteries to dead in one night other than fuses... Only when I have the alternator hooked up does the battery draw...

 

[Stu Bailey]

The alternator is cold but that's because it is cold outside and the truck hasn't ran since yesterday.

 

[Thewespaul]

The alt will usually be warm if it’s drawing power, so i would lean towards a bad regulator causing the parasitic draw. Since you have no change with the fuses out it means you either have a short to power in a circuit that shouldn’t have power all the time, meaning a circuit is getting power bypassing the fuse box, or it’s one of the hot at all time circuits that is using up the batteries. You can pull the fuses and check to see if any of the circuits on the output side of the fuse terminal have voltage with the fuse out. That test will help you narrow it down a lot

 

[Stu Bailey]

Thanks partner.

 

[franklin2]

Also look around the battery terminal area and the pass side inner fender where the ford style solenoid (starter relay) is located. Look for any add-ons the previous owner may have installed. Any added wiring here will by pass the fuse box.

 

[franklin2]

P.S. Check the "I" terminal on the regulator. It should have a red/green wire on it. If it has power all the time, then that will bring the alternator "online" all the time and drain the battery. This wire is supposed to go to the "gen" light in the dash, and then the ignition switch. But you never know sometimes what someone else has wired up.

 

[IDIBRONCO]

so i would lean towards a bad regulator causing the parasitic draw.

I had one do this on my 1981 F150 so I know that it can happen.

 

[Stu Bailey]

Right on guys. Thanks for all the help. I ordered a Motorcraft VR, should be here in a few days. I'll hopefully be back on with the reply of it works and is back on the road chewing asphalt. Merry Christmas ya'll.

 

[icanfixall]

My best idea is the voltage regulator has failed. If it can't interrupt The alternator charging circuit then the batteries are still connected directly to the alternator. That will drain the batteries over night easily. Recharge the batteries and disconnect them. See if the drain. I bet they stay fine...

 

[IDIBRONCO]

My best idea is the voltage regulator has failed. If it can't interrupt The alternator charging circuit then the batteries are still connected directly to the alternator. That will drain the batteries over night easily. Recharge the batteries and disconnect them. See if the drain. I bet they stay fine...

Or maybe you could try to unplug the old regulator while leaving the batteries hooked up. I think this would tell you if it's the regulator or something else.

 

[Stu Bailey]

New voltage regulator in and she runs great again. Thanks for the help amigos.

 

[IDIBRONCO]

Great! Simple fixes are the best ones.