Hey everyone, I am in desperate need of some guidance. To start I am mechanically savvy, I built my Marauder and even supercharged it. But this issue with my F150 is giving me a run for my money. On Friday I went to run an errand and immediately the truck was missing, but no miss codes. The oil light was on and the oil gauge bottomed out, the truck was running and given my knowledge of mod motors from the marauder I knew I had oil pressure. Driving down the road the light would turn off and the oil pressure gauge would come back, then repeat until it finally went away but the truck still ran like crap. The truck ran terrible during this errand, and when I got home I put it in park and pushed the throttle down briefly, the oil pressure light/gauge issue happened again, but the same happened to the coolant gauge (bottom out then come back) and the odometer went to ----------- briefly. I've parked the truck since then Friday, only moving it in the driveway once yesterday and issues still persisted.

The issue definitely seems to be electrical, and the only code showing was in relation to an exhaust leak I have had for a while now that will be getting fixed this summer. I could really use some advice on where to start or what to look for as this is outside my scope of experience. This is my daily, so anything is appreciated. For this week I am borrowing someone else's car.

 

Has it rained where you are located recently?

 

I've never experienced any leaks inside, but it did rain Thursday. Notably when I went back inside the house to get my wallet I left the driver door opened and came back after 30 seconds, the seat and door was a little wet, the floor was wet as well. Are you thinking doing that would have damaged the GEM I have read about?

 

Yes, that is what it sounds like to me. The drivers floor being wet is an indicator that the GEM is getting wet.

 

We had one hell of a downpour here on Saturday. My Expedition that I thought was fixed had a couple of little drips on the floor. I think what saved it was the little protector I made for it. I got a sheet of PVC plastic and made a shield for it.... but I still need to get this damn thing sealed up.

 

Mine was leaking here....



And doing this on the floor mat....



It is much much less water now, makes me wonder if it's a different spot now. I was sure this thing was sealed in that corner now.

 

Well I'm happy to know what it most likely is, however irritated with the amount of work ahead of me to fix this and keep it from happening again. Do I need to get the GEM programmed at the dealer for my VIN?

 

Also to add to that question, I have the work series truck. No CD player, no power anything, nothing. It has rubber floors, heat, and 4x4 on the floor stick. That's it.

 

I don't think it's GEM related personally. Cluster, PCM diod possibly, PDB under the hood, bad ground...I don't recall what you have going on as a wet GEM trait...ever. Wet GEM would be your 4x4, windows, starter/ignition. White, have you heard of GEM related cluster problems in the past ? Anything going on with the starter or has the truck acted funny in the past after it's sat out in the rain ? Any little hints before it got bad ?

I just read that you have a fleet truck , manual 4x4, no power windows.

Iduno, seems electronically it's all in the cluster right now. Your gauges going goofy like that COULD be putting the truck into Fail Safe Mode.

I'd start at the cluster, remove and inspect for shorting/carbon traces. These trucks have cluster PCB issues. Cracked solder joints that you can re-heat and fix, other times you'll find a cooked a resister. There is some info about that on the net. Look up "F150 cluster problems".

 

I read a post from that search, one thing that came to mind is when I shift the truck out of 4x4 in P or N, it doesn't always take. Usually after the truck has been off for a bit, or eventually disengages while driving after. I see the GEM also controls this? That problem I have had for about a year now. I figured it was something else?

It sounds like a GEM issue, but then I think it sounds like a bad ground somewhere. Where are the grounds located? I see the one in the engine bay at the back, I checked that and its good.