Tried to start my truck after sitting for 2 days in sub zero weather. wouldn't crank. pulled the batteries and charged them over night. Tried to start it the next day-wouldn't crank but the starter relay clicked. Was going to pull the starter and check it but decided to replace the relay first. replaced it and tried to start but now have no power to the cab-nothing comes on. I've checked the batteries with a load tester and they are ok. I've checked the fuses and they seem to be ok. when I tried to start it and the relay clicked there was a loud buzzing noise that seemed to be coming from under the dash. it has done this before but this time was louder than usual. I live out in the sticks so taking it somewhere is a last resort. any suggestion would be greatly appreciated. great site. It is a 1999 7.3 with 290000 miles. thanks

 

Look for a wire that you might have missed on the solenoid. There is a few smaller wires with the large battery wires, they power the whole truck.

 

can't find any wires that aren't connected or appear to be damaged. there is 12.6v going to the starter solenoid. the only small wire I see is the that plugs into the starter relay. does the current run from the batteries through the starter to the fuse o in the engine compartment and then into the cab? thanks for the help.

 

You have one big fusible link that comes from the battery side of the starter relay and goes to the power distribution box. If it got damaged you will lose power.

 

You may have put one of the smaller wires on the wrong large terminal. Are there any on the side that goes to the starter?

It was doing one thing, you replace the starter relay/solenoid and now it's not doing anything. That is a big hint where to look.

 

If you put the feed for the power distribution box on the wrong starter relay terminal, not much will work right.

At the relay, there should be one heavy wire all by itself that goes to the starter, one small wire that goes to the small terminal, and everything else HAS to be connected to the relay stud that also has the wire from the battery(ies) positive terminal(s). That's the basic way the relay gets hooked up.

 

Made some progress in that now have power back to the cab and everything seems to be working. But now the engine cranks but won't start. This happen once before and turned out that the pcm was fried, had a chip in and it went south, expensive lesson. The service engine light came on a few weeks back so bought a scanner but it won't read diesel so for now I can't pull the codes. The batteries have been sitting out in the cool Montana nights so recharging them and see if that helps.

 

You must have one of the cheap parts store handheld ones. Most of the good ones will read any of the OBD-II codes, I know mine will.

 

If you have a generic code, any obdII code reader will read it, it doesn't matter if it's diesel.

What does your code reader say?

 

If you have a generic code, any obdII code reader will read it, it doesn't matter if it's diesel.

What does your code reader say?

 

The scanner is an Actron cp9575-obd2-can. shows misfire monitor o/k. everything else is n/a. the starter relay clicks continually when I try to start the engine.

 

I would check the battery voltage at the relay while trying to crank. A chattering relay is a sign of low voltage reaching it under load.

 

Yes, bad batteries, low batteries, bad cable, loose connection.

 

charged the batteries and they show 12.6. don't have someone to help right now but turn the key to start and the relay shows 12.1 I'll have a friend to help in a few hours and will test the relay while trying to start the truck.

 

Yes, like Bill said make sure to check with your meter while someone is springing the key over to crank.