Electrical issue.

[Mattykillzya]

let me first introduce myself. My names matt. I live in johnstown colorado. I bought my first cucv about a month ago. 1984 m1009 cucv.

when I first bought it, it would start hard and the started would turn slow and hardly any of the lights on the dash worked. After a little investigation, mostly on here, there's a ton of useful links and help on here, although I can't find my specific problem. I found my batteries were running in parallel instead of a series. I re wired them into a series and volia starter turns over barrier and all the lights came on and everything was working.

now my problem is that I've blown the fuel shutoff solenoid. It wasnt clicking so i pulled the cover on the IP and it was not working. I checked voltage and there I 24 volts at the IP and for the entire truck. All of the ignition and inside of the truck is at 24 volts. I'm sure it's a simple thing I'm missing, but I can't find a step down to get back to 12v for the required stuff.

any help would be appreciated.

 

[Barrman]

The batteries are in series for the 24 volt part of the truck. However, the 12 volts for the 12 volt side of the truck is pulled from the ground wire of the back battery. I know that makes it as clear as mud. The -20 Technical Manual has a great 75 page electrical trouble shooting section plus appendix E I believe it is that is nothing but wiring diagrams.

 

[Mattykillzya]

The batteries are in series for the 24 volt part of the truck. However, the 12 volts for the 12 volt side of the truck is pulled from the ground wire of the back battery. I know that makes it as clear as mud. The -20 Technical Manual has a great 75 page electrical trouble shooting section plus appendix E I believe it is that is nothing but wiring diagrams.

I've looked at the diagrams, and can't find specifically where it mentions the 12 v side. I'll look at them again.

 

[Mullaney]

let me first introduce myself. My names matt. I live in johnstown colorado. I bought my first cucv about a month ago. 1984 m1009 cucv.

when I first bought it, it would start hard and the started would turn slow and hardly any of the lights on the dash worked. After a little investigation, mostly on here, there's a ton of useful links and help on here, although I can't find my specific problem. I found my batteries were running in parallel instead of a series. I re wired them into a series and volia starter turns over barrier and all the lights came on and everything was working.

now my problem is that I've blown the fuel shutoff solenoid. It wasnt clicking so i pulled the cover on the IP and it was not working. I checked voltage and there I 24 volts at the IP and for the entire truck. All of the ignition and inside of the truck is at 24 volts. I'm sure it's a simple thing I'm missing, but I can't find a step down to get back to 12v for the required stuff.

any help would be appreciated.

.
Hi Matt,

Welcome to the Outfit! So, you were given the information about the TM's (Technical Manuals) by @Barrman . He has been doing this for a while. Good guy to help solve some of your issues.

What if you gather a few pictures and post them here? A few of the outside - just because we would like to see what you have - and several under the hood with focus given to the firewall and the batteries and alternators. Factory wiring seems to get hacked up to make it more civilian - but then the rest of the truck isn't happy. Starter and Glow Plugs are the only 24v pieces on this vehicle.

Hope that helps a little and maybe with pictures - if it isn't hacked up too badly, we can be more useful. Again, welcome to the group! Looking forward to some pictures...

Tim

 

[Mattykillzya]

.
Hi Matt,

Welcome to the Outfit! So, you were given the information about the TM's (Technical Manuals) by @Barrman . He has been doing this for a while. Good guy to help solve some of your issues.

What if you gather a few pictures and post them here? A few of the outside - just because we would like to see what you have - and several under the hood with focus given to the firewall and the batteries and alternators. Factory wiring seems to get hacked up to make it more civilian - but then the rest of the truck isn't happy. Starter and Glow Plugs are the only 24v pieces on this vehicle.

Hope that helps a little and maybe with pictures - if it isn't hacked up too badly, we can be more useful. Again, welcome to the group! Looking forward to some pictures...

Tim

Thanks for the welcome !

At this point I've disconnected the batteries to start over from square one. I think the previous owners hacked the wiring a little, but hopefully not too bad.

I've been studying the TM's. It almost looks like I have extra wires some places and not enough other places.

Look forward to some ideas after pics !

 

[royalflush55]

Previous owner may have tried to convert it to 12 volt. You said batteries were hooked up in parallel. Check starter to confirm if it is 12 or 24 volt. 12 volt conversion will not start as strong with the same battery cables. 12 volt needs upsized cables to start strong. It still may not start as strong as 24 volt.

 

[GunnyM1009]

Looks like the 24v to 12v resistor is missing off the firewall. Someone has either done or halfway done a 12v conversion

 

[GunnyM1009]

There's usually a large resistor on the firewall behind the aircleaner. Only picture I could find quick.

 

[cucvrus]

I have a pile of the firewall resistors. I bought everyone I seen for sale in the past 20 years. I was told they were an issue. After 27 years I never had one fail yet but I always had extras and still do.

 

[Mattykillzya]

I have a pile of the firewall resistors. I bought everyone I seen for sale in the past 20 years. I was told they were an issue. After 27 years I never had one fail yet but I always had extras and still do.

where are you located and what would you want for One? Would I be able to wire it back in with no issues ?

 

[Mattykillzya]

Update.

I've hooked the batteries back up into a series.

Someone before me changed the GP relay and added some wires. One wire is running from the inside dash killswitch and running to the fuel shut off solenoid at the injection pump. I belive it is providing power back to the entire harness through this connection.

I also think the GP relay is working incorrectly.

When I bought the truck it ran and drove fine but the batteries were hooked up parallel instead of a series. I'm having issues getting it running back on 24 volts. I've added a few more pics. Any help would greatly be appreciated.

 

[Mullaney]

Update.

I've hooked the batteries back up into a series.

Someone before me changed the GP relay and added some wires. One wire is running from the inside dash killswitch and running to the fuel shut off solenoid at the injection pump. I belive it is providing power back to the entire harness through this connection.

I also think the GP relay is working incorrectly.

When I bought the truck it ran and drove fine but the batteries were hooked up parallel instead of a series. I'm having issues getting it running back on 24 volts. I've added a few more pics. Any help would greatly be appreciated.

.
That bus bar on the passenger side of the truck has no nut on the red wire to the right. The entire bar looks like it needs to be cleaned. It isn't horrible, but it looks corroded to me. You need to disconnect both batteries, then get yourself a tube of anti-oxidation paste and a few brass toothbrushes. Clean every contact that you see. And while the batteries are disconnected, remove the wires off the alternators and clean the wires and connection points too. Everywhere there is plastic holding wires (that plug into the alternator) for example need to be cleaned too. Small amount of Anti-Ox on everything...

 

[GunnyM1009]

It honestly looks like that has had a full 12v conversion. Without the glowplug resistor in it you may have sent 24v to 12v glow plugs when you put the batteries back in series. If you have 24v at the glow plugs you could have fried all your glow plugs. Also did you check the starter to see if it was 12v or 24v?

 

[Mattykillzya]

It honestly looks like that has had a full 12v conversion. Without the glowplug resistor in it you may have sent 24v to 12v glow plugs when you put the batteries back in series. If you have 24v at the glow plugs you could have fried all your glow plugs. Also did you check the starter to see if it was 12v or 24v?

I have replaced all the glowplugs. The starter is a

It honestly looks like that has had a full 12v conversion. Without the glowplug resistor in it you may have sent 24v to 12v glow plugs when you put the batteries back in series. If you have 24v at the glow plugs you could have fried all your glow plugs. Also did you check the starter to see if it was 12v or 24v?

I was think that as well but the way it was hooked up before, in parallel, none of the instruments lights worked. When I hooked the batteries up in a series all the lights and voltmeter turned on and worked. The starter is 24 volt and was turning over twice as fast as it was. I have replaced the glowplugs yesterday.

I might just hook it back up parallel and run it that way I guess

 

[GunnyM1009]

I have replaced all the glowplugs. The starter is a


I was think that as well but the way it was hooked up before, in parallel, none of the instruments lights worked. When I hooked the batteries up in a series all the lights and voltmeter turned on and worked. The starter is 24 volt and was turning over twice as fast as it was. I have replaced the glowplugs yesterday.

I might just hook it back up parallel and run it that way I guess

If it was in stock 24v configuration the only thing that should actually get 24v is the starter. 24v does go to the Volt meter but it has a resistor inline to make it 12v before it hits the meter it's a 12v meter with a resistor behind it. So if it's only getting 12v it's going to read no volts because of the resistor. That's about as far as my knowledge of the system goes I'm by far not as knowledgeable as some on here when it comes to the wireing on these things.

 

[royalflush55]

I have replaced all the glowplugs. The starter is a


I was think that as well but the way it was hooked up before, in parallel, none of the instruments lights worked. When I hooked the batteries up in a series all the lights and voltmeter turned on and worked. The starter is 24 volt and was turning over twice as fast as it was. I have replaced the glowplugs yesterday.

I might just hook it back up parallel and run it that way I guess

You have confirmed the starter is 24 volt?

 

[Mattykillzya]

You have confirmed the starter is 24 volt?

Yes, starter is 24v

 

[Keith_J]

This is yet another reason to keep it stock. I would print out the wiring diagram and see if anybody in the area has a stock CUCV for comparison. Very difficult to diagnose online.