starter

[ole]

I have a 1985 M1008. Engine will not crank, no audible click from starter solenoid. DB 24V starter was installed Nov. 2008. Batteries are checking O.K. Replaced the starter relay yesterday. 20 Amp ignition fuse O.K. With key turned on the 12V functions are working. Engine will not crank.
I suspect the starter is bad, but I don't have any electrical knowledge. What is the function of the starter relay in the starting circuit?

What can I check next with my limited knowledge of this system. Any help will be greatly appreciated.

Thanks, Joe.

 

[Warthog]

Did you replace the starter relay with same type? Have you ever heard of us talking about the Doghead Relay upgrade/modification?

The relay takes the 12v from the ignition switch, energizes the coil and closes the contacts, sending 24v to the starter relay on the starter. The starter solenoid energizes and closes its contacts sending 24v to the starter motor.

Sound like your DB starter has bit the dust. Pull it out and have it tested/rebuilt/replaced.

The TM 9-2320-289-20 technical manual has a troubleshooting section that covers this type of issue. It is a great starting place.

 

[ole]

I had a new relay and used it.
I just went NAPA and purchased a 7-01860-1 relay for $16.95
I called DB and they do not rebuild the starter due to cost compare to a new one. In 2008 I purchased a 6898 24V starter for 192.07 delivered and I just ordered a new one for $103.90.
I intend to install the new starter and hopefully start the truck.
Is there any time limit to install the Doghead modification?

Thanks again, Joe

 

[MarcusOReallyus]

Whoa, hoss. Slow down. Let's do some testing before you start throwing parts at it. That's the expensive and frustrating way to repair things.

Have you got a multimeter? If not, it's time to get one!

No time limit on the Doghead mod. It's a replacement of the original starter relay - the one under the dash. This relay is known to have problems, including sticking, which makes your starter run and run and run until you burn up some wiring. Not good. It's under 20 bucks, and money well spent. There's a sticky on it.

 

[ole]

What are the things that I should start checking? Is there any sequence to start checking? I just replaced the starter relay under the dash so far.

Thanks, Joe

 

[MarcusOReallyus]

Well, let's follow the juice from the battery through the circuit:

1. The key switch applies 12v to the starter relay under the dash. So, check to see if that happens.
2. The under dash relay should have 24v coming to it. Does it?
3. When key switch is engaged, do you get 24v out of the under-dash relay?
4. When key switch is engaged, do you get 24v to the starter solenoid?

Check it out and let us know, and we can go from there. Got voltmeter?

BTW, you can check those things in reverse order. If #4 is good, it's pretty safe to assume 1-3 are good. If 4 is bad, but 3 is good, you can assume 1 & 2 are good, and so on.

Your problem is downstream of whatever checks good. It's upstream of whatever is bad.

So, if 4 is bad, and 3 is good, your problem is in between. Get the idea?

If # 1 is bad, well, your problem is upstream of that somewhere. That's not really the first step, but since you mentioned the 12v functions seem to be good, I started there.

 

[ole]

Just getting back to working on truck. I have a voltmeter and two 8 foot leads. I plan to hook the red lead to the small wire on the starter and the black lead to the battery ground and the black lead don the voltmeter. Is this OK? The old starter is still in the truck. I will then turn the ignition switch to start the truck and read the voltage. If the voltage is 24V and nothing happens then is the starter bad ? Thanks, Joe.

 

[dstang97]

You don't need 8' leads get a friend to help you. Pretty much get a multimeter and test the Big red wire and make sure you have 24v. Then get a friend to turn the key and see if you get 24v's at the small terminal (the purple wire. )

Then report back

 

[ole]

The big red wire on lthe starter solenoid checks 24 volts. the small terminal gets no reading at all. checked it a number of times with the key turned to start position or not. The batteries are checking good and the 12 volt system is working. Thanks, Joe.

 

[dstang97]

Even with someone turnin the key? (Trying to start it) if yes make sure you are getting 12v at the starter relay on I believe purple with white tracer. With the key in start position

 

[ole]

How and where do you access this wire?

 

[dstang97]

Read all of the stickies and FAQ. The. Report back.