Changed my glo plugs and put on a new relay. Ford plugs and white Rodgers heavy duty relay. All went well. Started right up no more smoke all good I thought. Driving down the road and radio quit working airbag light flashed a few times and stayed on. Pulled over and stopped to see what code the airbag was flashing and no start. Like batteries are dead. Jumped and still no juice or not enough to turn engine. Power to lights but sometimes when I turn lights on the wipers start going. Wipers will also go sometimes when key is turned to start


Anyone have anything like this happen? My uvc harness looked good

 

Have you had a recent rain? That sounds like the GEM (behind the fuse box in the cab) got wet from a windshield leak.

 

Does the GEM affect starting the engine?

Did the battery cables get properly tightened? Did you use a post wire brush before installing the cables? Any signs of corrosion?

You could jump the starting solenoid plus side control wire from the battery and see if the engine cranks.

The symptoms say dead batteries. Have them checked. Bumpy roads are he!! on batteries. If the batteries get badly discharged, you cannot jump them to get the engine started. They suck all the power, leaving none for starting. Glow plugs alone draw over 100 amps, starter probably 400 amps, i dont' really know exactly, but it is a lot.
Larry

 

The headlight/windshield wiper thing steered me down the path, but flakey voltage makes perfect sense after repairing a high-amp item.

 

Initially the description sure sounded like a bad battery or alternator. Stop by Autozone or someplace to have them tested.

 

Vehicles do funny things when batt voltage gets low. What's the chance your new relay is bad from stock and staying on. That would drain your battery pretty quickly. If you don't have a meter handy turn lights on and remove lead to glow plug relay and see if lights get brighter

 

thanks for the help guys. had to leave the truck overnight in a parking lot 50 miles from home, headed back with tools soon.

battery connections where good, cleaned everything up nice and shiny when I put things back together but the batteries are over 2 years old and I rarely get much more than 3 out of them. will test them first.

Another symptom I failed to mention was the windows wouldn,t budge with key in the run position but would go up fine in the accessory only (back) position

I read a bunch about the gem last night and this truck has had a problem in the rain for the last 5 years or so. cuts out when wipers are on intermittent. If its not the batteries or alternator and the relay is fine Im wondering if that stronger relay is sending/pulling more juice than affected parts along the path have seen in a long time (the old one fell apart while I removed it) and the 10 or so starts increasingly wore something out?

All the starts after glo plug and relay replacement and before failure seemed fine, it acted up while driving which leads me to believe its something that is impacted electrically while driving.

if the relay is faulty and staying on what impact would that have on the new glo plugs?

 

Shortens their life! Pull the feed cable loose if that is the issue until you get it fixed.

A possible cause of the problem is that you have some short circuits on the load side of the contactor. If the relay contacts welded closed, which can happen with a heavy load, the control wire would not have any effect. But the load would quickly discharge the batteries.

If the contactor has failed, I suggest you check the two banks of glow plugs against each other to compare resistance. Or ohm out each individual glow plug. Short circuits in the glow plug circuits can load the alternator heavily, leading to a premature failure.
It is probably a good idea to just replace glow plugs when a truck gets a lot of miles on the odometer, just to minimize this type of problem.
Larry

 

just dont use a buckzooka on it.

 

Sounds like a batt voltage issue to me. It could be a stuck relay or the trigger/signal wire to the relay from the PCM is shorted to ground. I believe a good functioning set of glow plugs draw around 60 amps so if it is stuck on even the best batteries wouldn't last very long.

I lost an alternator once 20 miles from the nearest cell signal, as the batteries died all sorts of strange things occurred. Dash died,(no tac or speedo), wipers came on etc.

Your issue with the truck "hickuping" with the wipers set to intermittent is either a faulty CPS or a ground issue with the wiper motor or both.

 

That is an important clue. Is there anything else that works in accessory but not run?

 

I'm thinking ground issues all the way. When something comes on when you turned something else on tells me that a positive is drawing current from a source other than what it's suppose to. There are a number of ground wires on these trucks besides the negative leads from the batteries. Are you having any issues with lights? Are they all working?

 

Not as exotic as I thought. Got it running with a charger and a simultaneous jump showed no charge from alternator and batteries dropping from 13.5 to 9 volts after start. So new batts and alternator appear to be the solution if the alternator tests bad off the truck. As was said earlier low voltage creates some strange symptoms

 

Well its back. Alt did test bad off truck so replaced and two new batteries. Was charging good while I was paying attention but today all the same things happened again. No tools with me to test things but all accessories work with key turned backwards but shows dead or almost key in run position.

 

Do you have something like this

https://www.ford-trucks.com/forums/1...own-again.html

If you have some electrical component that is hanging up intermittently and pulling your voltage down a meter like the one in the thread above will let you keep a close eye on your system.