M1008 Electrical Problem. Motor keeps cranking when key is off

[usmc80]

I have been having trouble starting my M1008 lately. Thought it was the cold and a dying battery, so I charged them up and tried cranking it. I noticed a weird clicking noise seems like from the firewall but I couldn't tell from inside the truck. Then the truck kept cranking when I stopped and pulled the key out. The small wire attached to the battery running along the firewall got so hot it melted and I had to disconnect both batteries to stop it from cranking and melting the whole wire. Seemed possessed. Anyways Im thinking the problem is a faulty relay cylinder on the firewall. Can anyone confirm if thats the problem? Thanks

 

[MarcusOReallyus]

The way to confirm if that's the problem is to TEST it. You gots electrical problems, you need a multimeter. Under 20 bucks at your local home improvement store.


Have you done the doghead mod? This kind of thing is what the doghead mod is intended to prevent.

 

[Hasdrubal]

The glow plug relay on the firewall has nothing to do with the starter circuit.

 

[usmc80]

NO it is not modified and I haven't heard of the doghead mod. I know very little about electrical and I wasnt sure what was wrong or what to replace before I start ripping things apart. I will look into the relay mod tho.

 

[patracy]

Please view the sticky thread in this forum about the doghead mod.

 

[doghead]

It's a sticky.

It is most likely your problem.

 

[rsh4364]

Do the DogHead relay mod, When this happened to me I didnt know any better so I replaced burnt up fuseable link and replaced starter relay with another fact. relay,thought dang that wasnt bad,jumped in turned key and roasted my interior under dash harness all the way to the fuse box...was not happy and ignored her for about 4 months,she almost got parted out..glad I didnt now...Thanks to this site shes running great again,

 

[MarcusOReallyus]

I know very little about electrical and I wasnt sure what was wrong or what to replace before I start ripping things apart. .

Most people aren't, so you're in good company!


But no problem, just take things one step at a time. Don't start swapping, replacing, or ripping. Understand, test, then replace.

Too many folks just start blindly swapping parts, hoping something will fix the problem. This is the expensive and frustrating route. It's sometimes called the shotgun method, and sometimes called "spray and pray". It's what most people do.

Sometimes you guess right the first time, and this makes people think this is a good route, but it's not.

Start with understanding the circuit, and then think about what makes what happen. Then do some testing. If you don't have a voltmeter yet, get one!

In your case, the most likely culprit is that starter relay up under the dash. It's a known problem, and the doghead mod cures it.

 

[tequilaiam]

What you described is exactly what was wrong with my CUCV when I bought it. It was the common starter relay problem of getting stuck closed.

Simple way to verify: pull the relay under the dash, reconnect the batteries and try the key. The dashboard and blower should come on but it shouldn't crank. Make sure there's no copper from the melted wire touching the firewall when you do this. If that relay is indeed the problem, do the doghead mod and make sure you replace that burned up wire.

 

[ole]

Where can I find information on the dog head mod.

 

[patracy]

Where can I find information on the dog head mod.

In this very forum, stuck to the top of the forum post list.

 

[doghead]

post # 6

 

[MarcusOReallyus]

You need to set aside some time to read ALL the stickies. You'll be amazed at all the good info there. Start with the doghead sticky, of course.

 

[usmc80]

Hey thanks guys for all the info.

 

[Skinny]

You need to set aside some time to read ALL the stickies. You'll be amazed at all the good info there. Start with the doghead sticky, of course.

Congratulations on owning a CUCV truck!

With that being said, I agree. Put down all of your tools, do not touch the truck, disconnect the batteries. You NEED to read everything at the top of the forum for about two weeks while making a list of maintenance/repair items. When you are ready, knowledgeable, and have the parts...dig in. You WILL break something if you keep at it without reading like batteries, starters, cables, and possibly a post toasty CUCV if it goes to far!

Read, Read, Read again!