97 xlt intermittent issue with wipers, possibly alarm related?

[Bulldog_1995]

I've got a 97 with 130k, with power locks, windows, mirrors and a factory alarm, here's the issue
The wipers and dome light work only when they want, but both at the same time, never independent of the other, (ie if the dome light comes on the wipers will function normally, but if the dome light does not come on, the wipers won't either) and it seems to have to do with the alarm,
I've replaced the multi switch and wiper motor, and checked the wires, nothing was found.
They'll work fine until the alarm goes off, then no dice for a long time, any advice?

 

[RonD]

If its a factory Alarm then common element is the GEM(generic electronic module), its the Body Computer used in 1995 to 2003 Rangers
It controls wipers and dome light(door open), and is connected to RAP(alarm) module for door switch use and dome light

Does the dome light work all the time using the dimmer wheel, this is NOT thru GEM?
If so then issue is most likely GEM

The wiper switches(multi-function switch) have no physical connection to washer or wiper motor, they are wired to the GEM, and then GEM activates washer or wiper relays

Switch in each door is wired to the GEM, when door is opened GEM activates the Dome relay(also turns on Door Ajar light)
(the dimmer wheel switch sends 12v directly to the dome light)

The RAP module uses the GEMs door open to detect entry into vehicle

If it was just the dome light and alarm it could be a door switch issue, but when you add the wipers it points to GEM issue
There is no common fuse or 12volt wire for any of these systems

GEM is behind the radio, you would need to get the numbers off of it, and check connectors, could be just a loose or dirty connector
Any time you have a pin/slot connection that passes electrical voltage it can build up a residue between the metal parts, simply unplugging a connection like this and plugging it back in cleans off these metal parts and you get reliable connection back
I have read of people cleaning the circuit board and getting random issues to go away, so worth a try

 

[Bulldog_1995]

If its a factory Alarm then common element is the GEM(generic electronic module), its the Body Computer used in 1995 to 2003 Rangers
It controls wipers and dome light(door open), and is connected to RAP(alarm) module for door switch use and dome light

Does the dome light work all the time using the dimmer wheel, this is NOT thru GEM?
If so then issue is most likely GEM

The wiper switches(multi-function switch) have no physical connection to washer or wiper motor, they are wired to the GEM, and then GEM activates washer or wiper relays

Switch in each door is wired to the GEM, when door is opened GEM activates the Dome relay(also turns on Door Ajar light)
(the dimmer wheel switch sends 12v directly to the dome light)

The RAP module uses the GEMs door open to detect entry into vehicle

If it was just the dome light and alarm it could be a door switch issue, but when you add the wipers it points to GEM issue
There is no common fuse or 12volt wire for any of these systems

GEM is behind the radio, you would need to get the numbers off of it, and check connectors, could be just a loose or dirty connector
Any time you have a pin/slot connection that passes electrical voltage it can build up a residue between the metal parts, simply unplugging a connection like this and plugging it back in cleans off these metal parts and you get reliable connection back
I have read of people cleaning the circuit board and getting random issues to go away, so worth a try

Thanks for the advice, I'll check it out tonight after work

 

[Bulldog_1995]

Success! Replaced the gem and everything seems to be working fine now, thanks for the help

 

[RonD]

Good work

Thanks for the update, and THE FIX