I have a 2002 F150 that started having electrical issues a few months ago. It started with the radio and radio illumination periodically shutting off while driving. It did not seem to have a specific cause. Then last weekend while up in the hills, with the 4 wheel drive selector switch set to 2H the 4x4 light in the dash started cycling on at random and a relay in the fuse box (I think) would click at the same time. (I believe it is the accessory relay that is clicking). When I got back home I parked the rig and pulled the keys and the door chime continued to chime until the door was closed.
Things I have checked:
Radio connectors in the back of the radio and the boards in the radio for bad components or hot traces.
Swapped the relays.
Pulled the fuse block and GEM Mod to check for moisture and/or corrosion and found neither. Board in the Gem looks great all the connections are clean with no signs of heat.

Any help on where to look next would be greatly appreciated......

 

It sure does sound like the GEM. Do you have a garage nearby that can put their scanner on it?

 

I have an appointment on Thursday, I'll let you know what they say.

Thanks for the advice.

 

Well, I borrowed a code reader from a buddy and plugged it in this afternoon. The GEM passed but the PCM failed:
P0703 BOO (Brake ON/OFF) switch circuit fault
P1000 fault On-Board Diagnostic (OBD) System Readiness Test Not Complete.
P1780 OCS (Overdrive Cancel Switch) out of Self-Test range

I cleared them and tested again and only got the P1000 fault back.

Then after another test the GEM came back with with 2 faults.
P1438 Wiper select switch circuit failure
P1450 Wiper select switch circuit failure

Drove the vehicle again in a controlled setting where I could pay attention to the truck instead of the road and one of the relays that clicks when the 4x4 light blinks on is the PCM relay and after pulling it while driving there is another clicking relay in or behind the instrument cluster that clicks at the same time.

Any thoughts or ideas while I still have the reader tonight?

 

After posting the last I thought about checking the fuses again. I checked them before plugging in the code reader and testing, but not after. I found that fuse 29 (Autolamp Module, Overdrive Control Switch, Central security Module, Belt Minder) fuse was blown. After replacing the fuse I ran the reader again and came up with 4 faults (3 GEM and 1 PCM)
PCM:
P1000
GEM:
B1428 Safety belt lamp failure
B1398 Left Power Window Relay circuit failure
B1365 Ignition start switch battery short

Thanks in advance for the help.

 

How do you pull the PCM relay and it still runs? I assume that is the "powertrain control module" relay?

You are getting in over my head little bit. Maybe someone else will chime in.

 

Wow, My Bad! Read the page wrong..... It is Relay 2 which is the battery saver relay. (fuse 2 is the PCM fuse) Sorry for the confusion.

 

WooHoo! The good news is I think that I found the issue. I found a loose ground (loose as in missing screw and dangling behind wiring harness) in the drivers side kick panel. Once I attached it behind the harness mounting bracket, he radio came back on and all of the codes short of the PCM 1000 cleared. According to everything I have read the P1000 code may take a little bit to clear or it may be a whole separate issue. The Overdrive fuse that was blown earlier may also be a separate issue that I will keep an eye on.

Many thanks to Franklin2 for your time and feedback with the issue!

I'll let you know if it truly cured or cursed.

 

None of those are PCM failures, they, except for the P1000, are failures of the scan tool operator to follow the directions required during KOER testing. The P1000 is not a fault code anyway, it's an advisory that the PCM's memory has been cleared and the PCM has not yet had time to run all of its self test monitors.

Hope the ground wire fixed the issue. Usually, open grounds in that area have a different set of symptoms.