m1078 recovery

[Kswiney]

Yesterday we won our first m1078 out of Ft. Hood. We are about 2 hours away so we decided to pick it up ourselves. Tim assisted us in the recover. He went above and beyond. He had the truck practically serviced and ready waiting on us. We then left Ft. Hood on our journey home. The truck runs and drives great. Minutes after we leave I noticed the volt meter was pretty low. I talked myself into believing it would come up after a bit of running. Well we pulled into a gas station about 10 minutes into the trip and after fueling the shifter was acting strange and wouldn't go in to gear. We then realize the batteries must be shot. I pop the cover and discover only 2 batteries. I then called Tim and let him know. He immediately came out to replace them. Wow I was blown away but it's about to get better. After Tim showed up and started working on the batteries he tells me the alternator is shot. Before I could say anything he tells me just to hang on. That he will run get one and put it on in no time. My mind was blown can't thank them or GP enough. After he gets them swapped he tested the alternator and sent us on our way.


Along the way a few things happened and I am hoping for some help and feedback already looking through the TM's FYI.
So the volt meter still was showing low right around 24. We thought It would come up over the trip but did not. Here it gets strange at least to me. For the first 30 minutes the truck reads 165ish degrees. Then slowly starts climbing up to 200 over the next 30 minutes. So after an hour of driving this thing says its only 200 degrees and the fan had yet to come on. As soon as it hits 200 it comes on and the engine cools down. It continues to do this for 1/2 hour. Then the fan stops coming on. So I start really watching the gauge. At 210ish still nothing then the trans light comes on. I pull over and let it cool down the temp gauge still reads 210 or so. After a cool down we continue for 1/2 and hour and it happens again. So we pull over and let it completely cool down while we eat. I did a quick search while eating about the temp sensor. I pop the hood and check it. It was so loose when I touched it it came unconnected. I plugged It back in and continue. After another 30-40 miles the engine warning light comes on and the stop light. So I pull over and check that connector and wait a while. The lights go out the gauge still reads 200 or so. After It cooled to well below this we took off. Almost to the house the low beams just drop out and then the high beams. I replaced the relays but with no luck. And now the voltage is super low again. Any ideas? Thanks in advance.

 

[coachgeo]

Use favourite search method of this forum for Suprman, Alternator, wire. This should bring up several post from Suprman about a common wiring issue. The wire's that start to break apart are ones that carry voltage to the volt regulator on the Alt. This voltage is needed to tell Alt. to fire up. Without regulator relieving voltage via these wires, the alternator is not activated, thus no steady 24v is created. Without steady 24v a lot of things go wonky.

 

[Suprman]

Disconnect both regulator wires and tape them up. Come off fuel solenoid positive to front regulator terminal marked 24v see if that fixes the voltage issue. Verify with multimeter.

 

[NDT]

I have found that no matter how discharged the batteries are, if the alt is charging, the voltmeter will read in the green.

 

[Oxyacetylene]

On the headlights, I had a similar problem. The fix for me was to tighten up the connectors inside the relay sockets. They are just female spade connectors and they become loose over time. I used a small screwdriver or pick to slightly bend out the contact pieces a little so they would make better contact. It might also help to clean them up with some contact cleaner, like Deoxit D5. The retainer pieces are bright yellow and on some of my relay sockets you can see those have turned brown due to bad contact causing high heat at the connections. The poor connections will also cause the circuit to draw more amps and can pop the breaker. Not saying this is your headlight issue but I would definitely recommend taking a close look.

 

[Kswiney]

Thanks for all the replies. I am about to start working on her today. Suprman forgive my ignorance but I don't understand your reply(what I need to do).

 

[DiverDarrell]

He is saying the wires to the voltage regulatetor, unhook them. Then tap into the wire going to the fuel solenoid and run this power to the 24v on the regulator.

What this does is simplify how 24v gets to the regulator to initiate it producing power. The 12 and a/c are not used anywhere on the truck so you don't need them, but they can cause issues if hooked up and there is issues in the wiring.

 

[DiverDarrell]

From my experience with no voltage. Verify the positive and negative leads attached to the alternator. Mine were switched when I got my truck. Went through everything spent $$$, and all I had to do is hook a multi meter up, which should have been step 1

 

[TNriverjet]

Kswiney, what a great story! It's hard to believe you could win an auction and schedule pickup so quickly. I realize there is no EUC, but I think I waited almost two weeks on my generator just due to P/U schedule on the base. I'm glad you got home safe and are digging into repairs already. There is lots of good information and knowledge from helpful owners here on SS.

I drove my truck to a Family Fall Festival today and helped by hauling tables chairs and equipment before and after. The truck parked near the ball field sure helped attract attention during the day too! Everyone was interested in learning about the truck.

Make sure you post some pics of your new acquisition as you get a chance. Thanks!

 

[Kswiney]

Ok so we disconnected the wires on the voltage regulator and ran a wire from the fuel solenoid. The green light on the regulator comes on for a brief second then off. Voltage at the fuel solenoid is 23.7. Voltage on both posts on the alternator 24.5. I don't have 24 volts anywhere on the truck expect the battery and the alternator. Any ideas?

 

[NDT]

Which "both posts"? One large post should be 24 volts and the other large post should be 12 volts.

 

[Kswiney]

Which "both posts"? One large post should be 24 volts and the other large post should be 12 volts.

Both post on alternator 14v and 28 read 24.5

 

[NDT]

Both post on alternator 14v and 28 read 24.5

I'm thinking that is why your alternator is not charging. The alternator has internal protection logic that will not allow excitation if there are incorrect voltages at the posts. Someone has goofed up the wiring on your truck between the batteries and the alternator, or the reverse polarity protection device is defective somehow.

 

[Jeeperjoe]

Wait are you telling me you won an auction and then went and picked up your truck the next day