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I'm going to post my trouble codes from my Auto Enginuity scanner. This is the first time I've used the tool so I am not familiar with all of its functions.
I was suspicious of GEM before, and it looks pretty clear here but I would like another set of eyes on it before I shell out the money for a new one.
Also, the transmission light (on the shift ***) is blinking. Could this be part of the GEM issues?
The help is much appreciated. This truck is a fraud case. The odometer was rolled back and has many problems that I am trying to sort through now. Unfortunately, with COVID and race riots, the police and lawyers aren't being very motivated to resolve it. I guess I'll just move on and fix the POS. This is the first of many diagnoses I'm sure. If you have any suggestions for this scan tool, let me know.
Are you having issues with the transfer case shifting and with the wipers?
If you clear the codes, do they come back again? Want to make sure they are current codes.
If these issues are current, you can pull the GEM out and look it over for water damage. They can fail from a windshield water leak.
You can also run through the pinpoint tests in the service manual to isolate the GEM as the cause from several other possible causes (wiring, shift relays, transfer case encoder, connectors).
Some good information in the Tech Folder at the top of this forum, Electrical section, for troubleshooting GEM issues.
Its an early 99, F350 PS, Crew Cab, Long bed (looks like yours).
The transfer case selector does nothing at the moment. The wipers come on but they are erratic, sometimes stopping mid way and resuming seconds later.
I have never tried to clear the codes, this is my first time scanning it.
I have heard about the GEM failures because of water. I haven't inspected it yet, I will this weekend. Unfortunately the truck is total fraud and is not what it was reported to be. The odometer was tampered with, and I doubt they took care not to damage other parts ion the process. The interior has started to smell musty so I am suspecting a flood or leak in its past.
I did not know about the pinpoint test but I will definitely find it and perform that test. These GEMs are neither cheap nor easy to find. If I need a new one, It looks like I'll have to order from a dealership that can use a VIN check to verify compatibility.
Thanks you for taking the time to reply. It's a big help. This is my first personal use diesel, and its a dud so far.
I have been having similar problems with my truck. The 4x4 selector does nothing, the relays all checked out, fuses good, etc. The wipers were doing what yours are also.
Then my heater/cooler motor went out. So I replaced the motor and relay as suggested by someone on here. Fan started working perfectly again but so did the wipers. Not sure if or how it is connected by my wipers now work perfectly.
Electrical issues are always a challenge.
I will be watching this thread to see what you come up with.
The blower motor and relay were really not that expensive. Got them both on ebay (Motocraft parts) for around $75 shipped.
There's a post on here describing the process but mine was quite easy to do.
Maybe start there and see if your wipers start working again like mine did.
The wiring on these trucks is quite old and many times has been messed with by previous owners. This is why the pinpoint tests are necessary. I followed them and found no connectivity between my 4x4 selector switch and the connector pin that plugs into the GEM. Haven't had the time to run the issue down any further but hopefully soon.
Had similar issues with the 4x4 on my truck - pinpoint tests helped locate a broken wire, and loose connectors. GEM ended up being ok. Here's the link to that adventure:
These GEMs are neither cheap nor easy to find. If I need a new one, It looks like I'll have to order from a dealership that can use a VIN check to verify compatibility.
New GEM?
