No wipers.

[rasouth]

Hey guys... I have posted this problem before and have worked on it off and on, trying to narrow it down. The problem is my front wipers do not work when using the multi function switch, (turn signal). I have checked all relays, fuses, wires and connections, check for continuity, tested the MFS, (the resistance is all within specs, 47.6k off 11.2k middle and 0 high), replaced MFS, replaced motor and replaced the GEM. I narrowed it down to the wiring harness that plugs into the GEM. I have tested the wires coming from MFS to the harness and I get the same resistance readings as if I was testing the MFS itself. I have an OBD2 adapter that tests the GEM, and all the bells and whistles work; door windows, locks, 4x4 switch, rear wiper and washer and front wipers and washers and with this test the front wipers WORK!
I have opened the GEM, and for those who have not opened one and looked inside I might loose you in what I try to describe. Where the wiring harness fits into the GEM there are 26 connections. Two are a direct connection from the MFS, pink/yellow and light blue and orange. As I said before I took the reading of resistance at the harness and then plugged the harness into the GEM. By back probing MFS I get continuity to the corresponding pin on the back side of motherboard. Thinking I would get the same resistance by checking the back side of the GEM where the pins are soldered into the motherboard I get something totally different; 79k in off position, 73k in middle range and 0.3 ohms in high.
Testing shows that the wipers work when tested with the OBD2 adapter, testing shows I get the correct resistance reading from MFS to wire harness but MFS does not turn on wipers or washer. I speculate that something in the harness is not making good contact with pins in the GEM. I can back probe the yellow/white wire coming from GEM and wipers work. I have tried slightly bending pins in GEM, I have tried sticking small pieces of wire into harness to make a better connection and now I am at a loss for what to do.

 

[974X4BLACKSPORT]

Hope this helps.

 

[96eb96]

If you replaced the GEM (which has some problems with connections from posts I've seen in the past) and wiggle the harness and it works the next is is to replace the harness.
You may have to get a scrapyard GEM pigtail and solder or twist crimp the wires with heat shrink.. Connectors go bad over time. Some Ford terminals can actually be repaired, there are special kits for that with different pins. You stick a special pointed tool in the hole and it releases the contact pin.

You may also want to check resistance on the harness itself, from switch to GEM, see if there is a bad wire in there.

 

[CDW6212R]

I'd also aim at the connections. Given the main parts replaced, and the MFS being a best brand(prefer Ford), look closely at the terminal connections. Look for any one that has the tiny plastic lock missing or broken. It's easy for a terminal to push back away from the other terminal if the lock is not engaged. That is kind of common to turn out to be an answer when some other electrical issues pop up relating to main PDB wiring. The relays and fuses inside get R&R'd occasionally, so over many years any issue can be the terminal being "out."

Those connections for GEM etc, are rarely disturbed, so it is a long shot. But give it a shot, I would probably try another MFS first though. I've had one that was bad when new, a NOS Ford part.

 

[rasouth]

I have two MFS and both seem to work properly, so I think I can rule out the switch. I also have an extra GEM that I bought when I thought the problem was the GEM. It came from an exact same year, same model, same accessory type vehicle with the same serial number, so I think I can rule that out, too.
The resistance is the same at the harness as it is at the switch. It just seems that the signal is not making it from harness to the GEM, even though I get a continuity reading from switch to back side of GEM.
The washer does not work if I press the knob in on the switch because, from my understanding, the washer will not work if the wipers are not functioning. Both the wipers and washer work during the OBD2 test, so I am coming to the conclusion that it is in the harness itself.

 

[Turdle]

there are wiper relays, and also washer relays. I think the wiper hi lo relay is in the power distribution box, and also, you might check the relays under the air filter box as I believe the washer relay resides there. Swapping relays around might help pinpoint the issue, it may not but it's worth a shot

 

[CDW6212R]

That's a very good thought. Everything is 20 years old now, the relays are all suspect this old. Swap those around, and replace any that don't seem perfect.

 

[rasouth]

Everything works when testing with the OBD2 adapter. It's just that the resistance output from MFS is not making it into the GEM.
Please read the entire first post in which I stated:

I have checked all relays, fuses, wires and connections, check for continuity, tested the MFS, (the resistance is all within specs, 47.6k off 11.2k middle and 0 high), replaced MFS, replaced motor and replaced the GEM.

 

[CDW6212R]

If you have identified the wires related, I'd next try to jump the signals with a jump wire. Make it work, and then you know which wire, hopefully it's just one.

 

[rasouth]

I thought about that but the pins on the GEM are so freakishly small that I can't figure out how I would put a jumper on them. The two pins are right next to each. The pins are probably a millimeter or two wide and not much of a gap between the two.
With all the work I have been doing on the GEM; pulling wire harness, resistance testing, pulling the radio out, etc... my rear wipers are not responding now. Washer is but not wiper. I jiggled some wires on GEM and they worked and then didn't. Weird thing is they are on a different plug than front wipers. More problems!

 

[CDW6212R]

The smaller terminals are even more fragile. You hate to have to probe any of it if possible, for fear of hurting anything. Only use tiny probing objects to test circuits, or at the terminals themselves. I'd use a pin sized object to contact the back of those tiny terminal connections. If you can determine if the break is in the wires, then you can trace that or replace it. The terminals and connections themselves are more difficult to repair, it's best to replace those items if possible.

 

[rasouth]

I've been using safety pins for probing anything tiny, as those seem to be small enough not to damage much.
The two wires that come off the MFS tabs that you test for a good switch (tabs 13 and 14), I back probed the wire harness that plugs into the GEM and did get the correct resistance reading (pink/yel and gray/lb) . I then gently probed into the harness itself and still got the correct resistance reading. It is at that point that I plug the harness into the GEM and get nothing, no reading of resistance, yet if I test with the OBD2 adapter the wipers work, so the problem, to me, seems in the connection of the harness to the GEM not making good contact.
I'm thinking that with all the testing, probing and pull harnesses out that I might be doing more damage to it because of now my rear wipers are not working. I think I will find me another harness and replace it.

 

[CDW6212R]

The pigtails of many connectors can be bought alone, all common ones at least. I'd check to see if that might be available, that would be simpler than finding a used one to cut off.

 

[rasouth]

I did look to see if any one might have a replacement harness (RockAuto, Autozone, Ford...) but nobody had anything that would work.
Seeing on how small these connections are and how they are connected in the harness itself, I feel more comfortable with just cutting another harness out and splicing the two together. I have looked and tried to remove the wires but had no luck.

 

[rasouth]

Does anybody know if a GEM can be bench tested outside of the car? Before I start cutting all the wires and going through the trouble of splicing the wires on a "maybe" hunch, I would like to be sure it is the harness. I have two GEMs, the original that I thought was the problem, and a second that I bought from a salvage yard that did not fix the problem. It could be that both have the same problem with the wipers but I don't know. Everything else seems okay; i.e... MFS, relays, motor, fuses... I get continuity between switch and harness, I get the correct resistance between switch and harness, wipers work when testing with OBD2 adapter, etc... Am I missing something? Not testing the right wires? Do I have two bad GEMs?