No start help

[KP24]

This site has been a huge help for me and provided me with a ton of useful information thus far so I would like to start about by saying thanks in advance for all your help.

Now on to my issue. I have a m1008 that I have been working on and was starting it about once a week and letting in run for about an hour to keep the batteries charged. I have been doing this for a couple months with no issues until recently the truck wouldn't start. The battery indicator was in the red and the gen 1 and 2 and oil pressure light would stay on and the truck didn't start. The first thing I did was pull the batteries and hook them up to a charger. Once they were recharged I plugged them back in and had the same issue only now it sits in the red then I hear a click and it goes to mid yellow on the indicator. Still no start and gen 1 and 2 and oil pressure indicator are still lit. It doesn't even try to turn over or attempt to do anything when I try to start it. Hopefully my description isn't to vague and someone can point me in the right direction so I can figure out what's going on and fix it. Thanks again for all your help

 

[cucv1833]

How old are the batteries? Did you get them load tested? Are all the terminals clean on battery clamps and bus-bar?

 

[hotdogs151a2]

Mr. KP 24:
Mr. cucv1833 is correct. Even if the batteries are fairly new or new, have them tested. That is the first place I always check.
Thanks, Pvt. Hotdog

 

[wallew]

Have you changed out your BATTERY CABLES YET? Chances are high that they are corroded INSIDE the plastic sheath...

Just something to think about.

 

[DonK]

After checking the Battery Cables and connection, if you still have nothing, check for voltage at the starter. If nothing, work back checking voltage at the Starter relay under the dash and go from there. I had a similuar situation with my oh9, turned out to be a loose connection at the starter. And if you haven't done the Doghead Mod...get er done...

 

[KP24]

Thanks for all the responses. I checked both batteries and they both are putting out 12.7 Volts when isolated, and 12.5 volts when connected with the key in the on position. Both alternators are at 12 volts. I pulled the starter relay and decided to start checking and the red is getting 22.1 volts, nothing off of either purple wires. Not entirely sure what my next step it. Thanks for all the help and sorry for having so many questions.

 

[sierrajcharlie]

At the starter relay, the red is your 24 volt feed to the relay. The purple is the 24 volt switched to the starter solenoid. The purple with a white stripe is the 12 volt wire from the ignition switch. When the key is in the start position you should then have 12 volt on the purple/white wire and 24 or in your case 22.1 volts on the other purple wire. If not, you've got a bad relay. The doghead conversion is fairly easy and avoids having the original relay hanging and frying your starter. Good luck!

 

[WARWAG]

My guess is the starter relay is bad. If so be glad it didnt go bad while it was cranking over your truck!

 

[WARWAG]

Here is a how to and part numbers for the Doghead Relay Mod:

http://www.steelsoldiers.com/cucv/61184-doghead-relay-mod-my-m1028.html

There are other who show a how to but couldnt find them quick. This is the conversion I did to my M1028.

 

[KP24]

I went to napa and followed the doghead relay mod thats stickied at the top. Still no luck with a start using the key, I can take the red wire and tap it to the purple and it starts right up without any issues but still no juice ever goes to the purple white, regardless of key position, or the purple. I am not entirely sure if many the relay i got today happened to be bad, but that still doesnt explain the lack of power to the purple white wire...............

 

[cpf240]

Perhaps a bad or out of alignment ignition switch? Or maybe something to do with the neutral safety mechanism?

Time to get out the meter and trace those wires!