Electrical help needed.

[Firecloud]

Hi Guys,

Well, got the tires on, the rear window to work and a plow mounted to the front. I was preparing to wire the plow and now the truck will not turn over. I'm starting to think this thing doesn't want to go back to work. lol

So, I have lights etc..but when I turn the key to start the solenoid on the firewall clicks and so does a relay behind the dash but nothing else happens. I mean starter doesn't even try to engage. And if I hold the key for a few seconds smoke billows from the coils shown in the picture behind the heat shield. I've gone over a bunch of electrical connections with a voltmeter hoping to find any irregularities.

I either have 26.5 or 12-13 volts on connections. 24.7v at the starter. I'd say the batteries are weak and older but they have been starting it regularly unless it sits for a few days in the cold. My problem is that I don't know this truck yet or have any experience with a 24 volts system and a decent diesel experience, but with Land Rovers. Land Rovers have horrible electrical issues, but didn't expect it with a Chevy. I'm at a critical point where more snow is coming this week so just trying to get the plow wired so that I can hopefully use it soon. I should also mention that I removed the instrument cluster and took it apart to clean this morning. I focused on the electrical sheet that runs all of the dash lights.

Any ideas of what could be wrong?

 

[Firecloud]

Hi Guys,

Well, got the tires on, the rear window to work and a plow mounted to the front. I was preparing to wire the plow and now the truck will not turn over. I'm starting to think this thing doesn't want to go back to work. lol

So, I have lights etc..but when I turn the key to start the solenoid on the firewall clicks and so does a relay behind the dash but nothing else happens. I mean starter doesn't even try to engage. And if I hold the key for a few seconds smoke billows from the coils shown in the picture behind the heat shield. I've gone over a bunch of electrical connections with a voltmeter hoping to find any irregularities. I either have 26.5 or 12-13 volts on connections. 24.7v at the starter. I'd say the batteries are weak and older but they have been starting it regularly unless it sits for a few days in the cold. My problem is that I don't know this truck yet or have any experience with a 24 volts system and a decent diesel experience, but with Land Rovers. Land Rovers have horrible electrical issues, but didn't expect it with a Chevy. I'm at a critical point where more snow is coming this week so just trying to get the plow wired so that I can hopefully use it soon. I should also mention that I removed the instrument cluster and took it apart to clean this morning. I focused on the electrical sheet that runs all of the dash lights.

Any ideas of what could be wrong?

Here's pictures. What solenoid is this? And what is located behind the heat shield in the other picture?

Anyone have a Shop Manual that they'd like to sell?

 

[Guyfang]

You do not need to buy a shop manual. The TM's are here in the TM forum. Download them.

 

[Firecloud]

Oh, and last night the alternators were not charging one of the batteries. So, I put the front battery on a trickle charger last night without disconnecting the battery.

 

[MarcusOReallyus]

Start all troubleshooting with charged and tested batteries. Otherwise, you could be chasing your tail for a long time.

 

[Firecloud]

I finally broke down and ran into town for two new batteries. Still the same issue. I got all of the dash lights to work, but at the detriment of losing the starter!

Turning the key to "on" will seemingly warm the plugs. The "wait" dash light illuminates and I can hear the Glow plug relay click. I then try to start the truck and nothing. Stater solenoid is silent and it's like no juice is getting to the solenoid. It does however have constant current to the starter according to my voltmeter. If I leave the key on then the glow plug solenoid will click a few times at regular intervals. Once in a while it will "rattle" or vibrate for a few seconds. Would the glow plug solenoid keep the starter from engaging? I'm out of ideas and have worked all day on it.

 

[MarcusOReallyus]

Sounds like the GP circuit is working correctly. Whether it is or isn't won't affect your starter, so forget it for now. It's a distraction.

You have a relay under the dash that should be energized when you turn the key to the Start position. That relay should energize the solenoid on the starter. Check that relay to see if it is being fed 24v all the time. Then check to see if it gets 12v to another terminal when the key is in the Start position. If it does, check to see if 24v shows up on another terminal. One of the terminals is ground.

 

[Valor]

Hi Guys,

Well, got the tires on, the rear window to work and a plow mounted to the front. I was preparing to wire the plow and now the truck will not turn over. I'm starting to think this thing doesn't want to go back to work. lol

So, I have lights etc..but when I turn the key to start the solenoid on the firewall clicks and so does a relay behind the dash but nothing else happens. I mean starter doesn't even try to engage. And if I hold the key for a few seconds smoke billows from the coils shown in the picture behind the heat shield. I've gone over a bunch of electrical connections with a voltmeter hoping to find any irregularities. I either have 26.5 or 12-13 volts on connections. 24.7v at the starter. I'd say the batteries are weak and older but they have been starting it regularly unless it sits for a few days in the cold. My problem is that I don't know this truck yet or have any experience with a 24 volts system and a decent diesel experience, but with Land Rovers. Land Rovers have horrible electrical issues, but didn't expect it with a Chevy. I'm at a critical point where more snow is coming this week so just trying to get the plow wired so that I can hopefully use it soon. I should also mention that I removed the instrument cluster and took it apart to clean this morning. I focused on the electrical sheet that runs all of the dash lights.

Any ideas of what could be wrong?
[/Q

Hi Guys,

Well, got the tires on, the rear window to work and a plow mounted to the front. I was preparing to wire the plow and now the truck will not turn over. I'm starting to think this thing doesn't want to go back to work. lol

So, I have lights etc..but when I turn the key to start the solenoid on the firewall clicks and so does a relay behind the dash but nothing else happens. I mean starter doesn't even try to engage. And if I hold the key for a few seconds smoke billows from the coils shown in the picture behind the heat shield. I've gone over a bunch of electrical connections with a voltmeter hoping to find any irregularities. I either have 26.5 or 12-13 volts on connections. 24.7v at the starter. I'd say the batteries are weak and older but they have been starting it regularly unless it sits for a few days in the cold. My problem is that I don't know this truck yet or have any experience with a 24 volts system and a decent diesel experience, but with Land Rovers. Land Rovers have horrible electrical issues, but didn't expect it with a Chevy. I'm at a critical point where more snow is coming this week so just trying to get the plow wired so that I can hopefully use it soon. I should also mention that I removed the instrument cluster and took it apart to clean this morning. I focused on the electrical sheet that runs all of the dash lights.

Any ideas of what could be wrong?

Clean all electrical connections especially the ones to the batteries and starter, solenoid. Use wire brush, sand paper, steel wool, etc.

 

[Tinstar]

Being that your unfamiliar with CUCVs, it’s 24v system, and diesels, Download the TMs as suggested for reference so you at least know what your looking at and where things are located.

When you have a chance, Read the older threads and use the search function.
Everything your dealing has been discussed many times.

As already mentioned, low battery’s are a cause of many issues.
The New ones you installed removed one possible issue. Now you can move on to the next item.

Stock CUCVs, when properly maintained, are very reliable.
Getting them to that point can admittedly be difficult.

 

[cucvrus]

After reviewing the issues you have presented I would like to take a guess of the starter being bad. And it is not a waste of time at this point. Getting the CUCV starter refreshed as a precaution is not a bad idea. Why wait for it to fail? I would simply disconnect the batteries again and crawl under there and remove the starter. Take it to a local automotive electrical shop and have it tested and repaired or rebuilt. I have a local shop that rebuilds a lot of alternators, starters and any electrical issues. https://www.leidyrepair.com/

I left that there for you in case you need a reference. Also available and I would recommend just changing is
ACDelco P/N: 15591718 Starter Relay NSN: 5945-01-192-7985
This is located under the dash where the civilian radio would go. I recommend just changing the relay vs cutting the harness. Good Luck.

ACDelco 15591718

Free Shipping - ACDelco 15591718 with qualifying orders of $109. Shop Relays at Summit Racing.

www.summitracing.com

 

[cucvrus]

Now after reading over the symptoms again I feel that a close examination and testing of all the fusible links under the buss bar on the passengers side is needed. Make sure one of them has not melted thru. I would really check all the connections closely and make sure you have current. A test light is all I ever use. I have a Fluke volt meter but honestly barely know how to use it. I just get by with the test light and the volt meter. Call me simple I can accept that. This is an easy issue and needs to be addressed on an easy level. No tearing and hacking needed. The more you go changing the more issues you add to the mix. One issue at a time. Good Luck. We are all here to help. But the link wire may appear good by visional inspection but be melted out when tested below the link up stream.

 

[Guyfang]

The key to fixing anything is troubleshooting. Systematic testing of a system, starting at the front of the circuit, and working towards the starter. Test everything. And test it twice. Because when you test something and its good, that's one less thing to look at. Sounds simple/stupid, I know. But saves mucho time and money in the long run. Jumping from one part to another just wastes time. Throwing parts and money at it is fine if you have deep pockets. CUCVRUS is pointing you in the right direction. Open the TM, and get smart. The Troubleshooting diagram is in there. Ignore it at your own peril.

 

[Firecloud]

Thanks to everyone who has chimmed in! It's much appreciated. I couldn't work on it today, but hope to get back to it soon. It is blocking the garage stall that my Wife regularly uses which means someone's truck is going to be sitting outside until I get this electrical issue figured out. And ya'll know who's truck that's going to be!

I totally agree with everyone about learning the systems prior to diagnosing and I appreciate everyone's guidance. I'm a little frustrated because I have other vehicle projects and was hoping that I had not bought another in this CUCV because of Old Man Winter knocking at the door. But that's how it goes... I guess i was also hoping that it would have been better maintained by the Army, but I should have known better on that front, too. Now I know I am going to open a can of worms... I was Air Force (Crash/Rescue) and don't remember our trucks being so rough. Ok, lay it on me...lol
Seriously though, I've done a lot of restorations and modifications to some pretty complex Land Rovers, but this system is a bit different and whether I like it or not, I'll need to slow down and learn the systems and start diagnosing it correctly. Thanks for bringing me back to realty!

I'm looking into everyone's suggestions and will report back to this thread with my findings. Thanks again!!

 

[ehuppert]

If you can decipher a Land Rover you can certainly figure a Cucv out!

 

[ehuppert]

Is your pic wire getting juice at the starter when you turn the key to start?

 

[Keith_J]

The glow plugs and starter are 24 volt, the rest is 12 volt. To make this work, the 12 volt signal from the key switch on start position triggers a relay which sends 24 volts to the small wire on the starter. This relay is under the dash, look up Doghead relay mod. Yours might be bad.

The small wire to the starter moves the Bendix drive to throw the pinion into the ring gear, then it makes the main electrical contact so the fat wire on the alternator delivers current to the starter motor. You could have a problem with this solenoid on the starter.
Test both by measuring voltage on the small wire on the starter with the key in the start position. No voltage means the Doghead relay is bad. 24 volts and the starter relay is bad.

 

[Firecloud]

After all of that I found it was simply a bent contact on the starter relay. I now have a much better understanding of the electrical system. I went through most of the internal connections and cleaned them including the instrument cluster and the starter relay. Just didn't connect the plug correctly so itent the one lead.

Thank you everyone for your guidance. It's much appreciated!