Wiper issue

[artw45]

Got a "free" 95 ext cab 4x4 4.0 Auto Trans. Wipers not working, replaced switch, relays and got wrecking yard motor. Still no wipers, I was reading in another post that it could be the GEM Module? Also replaced the speed sensor in the transfer case and still no speedo, could they both be related to the GEM Module? There are a few Instrument clusters at the Wrecking Yard I could pull for the speedo.

 

[RonD]

Welcome to TRS

Yes in the 1995 to 2003 Rangers the GEM(generic electronic module) is the Wiper interface(2004 and up used SJB)
The switch is connected only to the GEM, and the GEM is connected to the wiper relays

No, in 1995-1997 Rangers the VSS is on the transmission or transfer case and doesn't need the GEM(1998-2000 Rangers did use GEM AND rear axle ABS/VSS for speed)
So check the gear drive on the VSS shaft in the transfer case

Odometer and speedometer share the one signal wire from the VSS, so if odometer is moving but no speedo then its a cluster issue
If both don't work then its a wiring issue

Example of wiring in 1995-1997 here: https://ww2-secure.justanswer.com/uploads/FO/fordguy4u/2013-05-22_172049_a1.jpg

The GEM does get the speed signal, it was used in some models to Lock the doors when speed went above 5mph, but GEM does not process the signal like in 1998-2000
The PCM(engine computer) also gets the VSS signal and will usually set a P0500 code if VSS not working, and it would turn on the CEL(check engine light)
So if there is no CEL then VSS may be working
VSS sensors generate their own AC voltage, so you can hook the VSS up to a drill and spin it, should see .5vAC to 6vAC depending on RPM of drill, thats AC volts not DC

 

[artw45]

Welcome to TRS

Yes in the 1995 to 2003 Rangers the GEM(generic electronic module) is the Wiper interface(2004 and up used SJB)
The switch is connected only to the GEM, and the GEM is connected to the wiper relays

No, in 1995-1997 Rangers the VSS is on the transmission or transfer case and doesn't need the GEM(1998-2000 Rangers did use GEM AND rear axle ABS/VSS for speed)
So check the gear drive on the VSS shaft in the transfer case

Odometer and speedometer share the one signal wire from the VSS, so if odometer is moving but no speedo then its a cluster issue
If both don't work then its a wiring issue

Example of wiring in 1995-1997 here: https://ww2-secure.justanswer.com/uploads/FO/fordguy4u/2013-05-22_172049_a1.jpg

The GEM does get the speed signal, it was used in some models to Lock the doors when speed went above 5mph, but GEM does not process the signal like in 1998-2000
The PCM(engine computer) also gets the VSS signal and will usually set a P0500 code if VSS not working, and it would turn on the CEL(check engine light)
So if there is no CEL then VSS may be working
VSS sensors generate their own AC voltage, so you can hook the VSS up to a drill and spin it, should see .5vAC to 6vAC depending on RPM of drill, thats AC volts not DC

Thank you, will check wiring on speedo. Wiper motor from wrecking yard doesn't even go into park, and checking relays there is power coming into the wiper run park relay on one of the two large blades, but not on the wiper hi low relay. I would assume this is the 12v power in and the relay connects the circuit to the motor with full power. So by it having power into the motor on the red wire coming into it and it not going into park, assuming that is the park motor my "new" motor may be bad and my old one good.

 

[RonD]

The GEM uses Ground side to activate the relays, not 12v

The run/park relay should have two 12v slots with key on
Then 1 Ground slot if wiper switch is ON and GEM is seeing its ON

Ford usually use the mini type relays, with is layout: https://www.gtsparkplugs.com/images/mini-automotive-relay-wiring-840x.jpg

85 and 86 active the relay, which connects 30 and 87 together
85 and 86 have no polarity, no assigned + or -, its just a coil of wire that becomes a magnet when it has BOTH 12v and Ground
So 85 or 86 will have 12v with key on
The "other one" will be a Ground IF.............GEM is grounding it, so test that with wiper switch OFF and then ON, to see if GEM is working

The high/low relay is the same, 85 or 86 will be 12v key ON, the other will NOT be a ground if wiper on and in LOW, will be a Ground if wiper on and HIGH is selected

Yes, Park may be bad in used wiper motor

 

[artw45]

The GEM uses Ground side to activate the relays, not 12v

The run/park relay should have two 12v slots with key on
Then 1 Ground slot if wiper switch is ON and GEM is seeing its ON

Ford usually use the mini type relays, with is layout: https://www.gtsparkplugs.com/images/mini-automotive-relay-wiring-840x.jpg

85 and 86 active the relay, which connects 30 and 87 together
85 and 86 have no polarity, no assigned + or -, its just a coil of wire that becomes a magnet when it has BOTH 12v and Ground
So 85 or 86 will have 12v with key on
The "other one" will be a Ground IF.............GEM is grounding it, so test that with wiper switch OFF and then ON, to see if GEM is working

The high/low relay is the same, 85 or 86 will be 12v key ON, the other will NOT be a ground if wiper on and in LOW, will be a Ground if wiper on and HIGH is selected

Yes, Park may be bad in used wiper motor

Found a 6 wire wire schematic and I have the full time 12v but not the park I have to assume that the GEM is bad at this point. Will check the wiring for speedo, took it for short drive and no speedo or odometer. Will check I assume it should have 12v going into speed sensor and ac coming out? Might go pull a 6 wire plug and run a fused wire to motor and check functions that way rule out motor.

 

[artw45]

One of the kids we had in our church youth group a few yrs ago gave it to our daughter for her first car. So far I have put in a new starter, oil change, fuel filter, trans filter, fuel cap, wiper combo switch, speed sensor, wiper relays and air filter. Still no wipers or speedo, got her a set of tires (Goodyear Wranglers) with 80% tread I need to get mounted for $200, next is brakes all the way around. She's 18 still doesn't have her license so need to make it safe and functioning. I had a 96 4.0 5 speed 4x4 that I loved, got rid of it with 292,000 and it didn't use a drop between oil changes.

 

[RonD]

VSS generates its own AC volts, .5vAC to 6vAC depending on how fast shaft is spinning

 

[artw45]

So this is where I am. New speedo sending unit and wrecking yard instrument cluster, still no speedo. New wiper switch, fuses are good, relays are good and I have main power to wiper motor (wrecking yard motor) have ground to both ground wires on plug.

 

[RonD]

The speed VSS is on the transfer case in 1995 4x4, its NOT the rear axle sensor as with other years

You can pull out that VSS and then use a drill to spin it, with key on you should see speedometer go up if wiring is OK
Can't remember which way you need to spin it, I want to say clockwise, but might be the other way, lol, doesn't hurt it to spin backwards, you do that every time you use reverse, but it won't show speed signal, just like in reverse

Transfer case speed sensor should look like this: https://www.therangerstation.com/tech_library/images/speed/vss_withgear.JPG
Two wire plug in, the gear comes off and can be changed to match new tire sizes to correct speed signal
There is a replaceable worm gear inside transfer case, the DRIVE gear, it can get striped, rare occurrence, but no speed signal if the smaller driven gear is not spinning.

And what about the GEM module?
As you can see in the 1995 wiper diagram then GEM needs to ground the wiper relays to activate them
The relays all get 12volts with key on from fuses 12 and 16 in cab fuse box, but are not grounded so stay off
The wiper switch tells GEM which wires to ground, which then activates that relay

 

[artw45]

The speed VSS is on the transfer case in 1995 4x4, its NOT the rear axle sensor as with other years

You can pull out that VSS and then use a drill to spin it, with key on you should see speedometer go up if wiring is OK
Can't remember which way you need to spin it, I want to say clockwise, but might be the other way, lol, doesn't hurt it to spin backwards, you do that every time you use reverse, but it won't show speed signal, just like in reverse

Transfer case speed sensor should look like this: https://www.therangerstation.com/tech_library/images/speed/vss_withgear.JPG
Two wire plug in, the gear comes off and can be changed to match new tire sizes to correct speed signal
There is a replaceable worm gear inside transfer case, the DRIVE gear, it can get striped, rare occurrence, but no speed signal if the smaller driven gear is not spinning.

And what about the GEM module?
As you can see in the 1995 wiper diagram then GEM needs to ground the wiper relays to activate them
The relays all get 12volts with key on from fuses 12 and 16 in cab fuse box, but are not grounded so stay off
The wiper switch tells GEM which wires to ground, which then activates that relay

Just did a test on the plug for the VSS and have no power, also found there was no fuse in #25 on fuse block, lots of dinging going on and abs light is on and gas cap light. It is still not throwing any codes through the OBD. Having a hard time finding where power should come from to the VSS?

 

[RonD]

VSS sensors, for speed or ABS, are VR(variable reluctance) type sensors, they generate their own AC voltage when the "tone wheel" next to them spins
.5 to 6vAC depending on RPM and teeth on the tone wheel

So there should be no power at any VSS(VR), and usually one of the wires will read as a ground, almost 0ohms to ground, as only the positive half of the AC sine wave is used for its pulse
So its not a "voltage sensor" in any case, its used for its Pulse, although you can use a volt meter set to AC Volts to see if VR sensor is generating AC volts when its tone wheel is spinning

Most crank sensors 1995 and up are VR type

In a 1995 Ranger Fuse 25 in Cab Fuse box, should have 10amp fuse that powers GEM module