Battery or starter ?

[Cdup]

Been having an issue with either a current draw while truck is off. Thought I fix the problem but lately seems like the batteries are getting weak. Got in the truck this morning and it turned over but a weak turn over. Stop and tried again and Only the starter solenoid would click. Check voltage at battery and both showed 12.3. Ran out of time to trouble shoot being I had to get the wife to bring me to work. Plan on checking to see if I'm getting 12v at starter when I get home tonight ..... Would accept any ideas or advice if possible weak batteries pending checking alt output .

[madpogue]

Is it the solenoid on the starter or the relay on the fender (the one on the fender is a relay) that's clicking?

Try putting the batteries on a slow charge. Separately if possible, but not critical. Then see if it'll start, and if so, wait 'til the glow plugs cycle off and check the voltage with the engine idling. It should be 14-ish volts. One simple test to see if it's a parasitic draw or just batteries that will no longer hold a charge - after you shut it off, disconnect both batteries and check the voltage. Should be 12.4-ish. Make sure they're separated. Then leave the truck and come back check again. If voltage has dropped on either/both batteries, they're the culprit. If they're about the same, then it's more likely a parasitic load.

Do you have a battery load tester?

[mydirtytruck]

I had the same issue and the starter was the problem.