More RAP problems

[56_F100]

Folks, I'm looking for some deep technical help. I've replaced RAP modules on my '97 Explorer (am on the 3rd one now), with all modules exhibiting similar symptoms. My original module code is F7CF-15K602-AB (the one with the antenna connection). I've replaced it with both suffix AA and AD modules. The last AD module worked fine when installed and I drove all day with one of our remotes working as it should. When I got home and tried programming the second remote, neither would program. Batteries in both remotes are new. Tried disconnecting the RAP module and reconnecting and as of now, here's what happens.
As reference, I always disconnect the negative battery cable before doing anything to the module. If I connect (1) the antenna, (2) the large 26 pin and (3) the smaller 22 pin connectors, the horn will sound and the parking lights flash (as if unauthorized entry) as soon as the battery cable is reconnected. If I leave only the small connector off, the horn & lights won't actuate, but if I leave only the large connector off, I get both horn and lights. FYI - this vehicle came equipped with the anti-static clips on both front seat tracks. I've removed the seats and inspected the clips - both are making contact with the tracks. I can't believe 3 different modules would go bad this quickly, and suspect something else. Any additional troubleshooting recommendations from you members would be appreciated since the guys at the salvage yard as starting to frown when I come thru their door.
Greg

 

[56_F100]

RAP problems solved - sort of

Well, the anti theft system is back in operation, along with some crazy discoveries. I replaced the latest RAP module while in the salvage yard's parking lot to ensure it would work, which it did. I took the time to reprogram both key fobs (transmitters) while I was there. When I got home later that day, the fobs would not work in the garage. Rather than trying a 2nd reprogramming, I drove the truck to the end of the driveway, about 700 ft from the house, and both fobs work fine. I then drove the Explorer back towards the house, testing the lock/unlock function every 50 to 75 feet. When I am wihin 75 feet of the house or between the house and shop, the fobs stop working. Any further distance away, and the system works as designed.

So figuring I have some RF interference, I started turning off "new" additions in the house and shop to find the source. I've done the wireless intercom, house alarm system, cordless phone, and wireless router. I even unplugged our new freezer (has digital display) and the low cost trickle chargers used on the street rod & RV and have had no improvement in the alarm system operation. We were able to use the remotes in the garage in the past, so something has changed that is interfeering with the fob signal. Will keep searching as time is available, but for now, the system works as designed, just not when the Explorer is close to the house.

 

[Runnin'OnEmpty]

Very interesting......
Are there any high voltage power lines running near your property? They will produce a magnetic field and disrupt electrical stuff.

 

[56_F100]

Rap problems solved - sort of

Nope, no high voltage power lines anywhere near the property, either buried or over head. We've been in this house for 6 years. During and after its construction, I used the fobs to lock/unlock the truck many times while it was in the garage. Therefore, I believe this interference problem is new - ie: within the last year or 2.