G'day,

Hopped in my truck today, a 2000 F150 XL 4.2L V6 and started driving, turned on the wipers, turned em off.. They won't go off? Any ideas? They randomlly just go on and off when they're supposed to be off, it's rather annoying.

 

Could be a few things.

1. Windshield leak causing water to get into the GEM / CJB ( aka Central junction box / cab fuse panel ). The rare option to this is a power moon roof that has clogged drain channels.

2. Issue with the end of the MFS ( multifunction switch ).

3. Issue with the wiper run / park relay.

Start by checking the floor for signs of water damage from a leaking windshield at the edge of the carpet on the firewall, and at the back of the driver's side kick panel ( remove and pull back the carpet.

If you have signs of water damage, get the cab of the truck covered until you can get the windshield reset.
While it is covered you can dry out the truck with a space heater or running the AC on high temp to dry out the truck ( a lot of idle time ).

If the floor has no signs of water, next would be to take apart the end of the MFS and clean the wiper contacts
https://www.f150online.com/forums/el...on-switch.html

This is the order to start in, until these are tested, no point in digging into the run / park relay.

 

I am also having issues with my wipers on my 1999 F250 LD not turning off (I rotate the **** on the MFS to intermittent - no wiper; then to lo - no wiper; then to hi - wipers run on hi; then back to lo or intermittent or off - wipers continue to run on hi) When I turn the key to off, they stop. I have to turn the key back on and they will return to park position.
I suspect the previous owner messed with the relays, cuz the horn relay was missing.
I was wondering if all the relays (horn, wiper run/park, wiper hi/lo) are all the same? Does anybody know for sure? ie Are they all the same part number?

I forgot to mention, I cleaned the contacts in the MFS as suggested. No change..

Update: Today (11/4/2011) I pulled the hi/lo relay and started metering contacts and checking to see what I had. I ran a jumper from the battery pos terminal, and stabbed the #4 socket and my wipers operated on lo. Then I stabbed the #5 socket and the wipers ran on hi. So I'm pretty confident the wiper motor is OK. I figured out that the "default position" for the relay is the lo speed, and for some reason the socket for the trigger pin has voltage, which would explain why they only run on hi. Now to figure out if it's the GEM or the MFS. Even though I cleaned the MFS, that doesn't mean it is not shorted someplace. Since it is easier to get at, I will start with the MFS.
Keeping my fingers crossed it's not the GEM!
I just found a troubleshooting/testing guide for the MFS on another site (sorry!). I will use it to diagnose my MFS tomorrow..
It can be found here: http://www.supermotors.net/registry/media/225114_1
(That site seems to be having "issues").
The following link also explains how to test your MFS
http://www.crownvic.net/ubbthreads/u...Number=2084345
Do a Google search for "MFS testing"

I also found this testing guide (for those people that know how to use a meter)




Hope it helps somebody else out. I hate to change parts in the hopes it fixes my problems...
This has been a real "edumacation", whether I wanted it or not!

 

Today I removed the MFS from my 1999 F250 to check the resistance on the wiper hi/lo/int terminals. I was "sure" I would find no resistance on anything when I hooked up the ohm meter. Instead what I found when I removed the covers was that somebody else (the "hammer mechanic" ) had already worked on the MFS, or maybe replaced it at one time. How did I know? Well this picture explains it (no, I didn't break the clips! ) I'm hoping I can secure them to the MFS (somehow, wire or glue?) because these are each $30 connectors!

Oh, the resistance checked out perfectly on the wiper switch circuit, right on the money. The switch is good!!





I also noticed a couple wires pulled out of the bigger connector. I read someplace in the forums that the cable assembly is a little snug, and when the steering wheel is tilted down, the connectors and wires get pulled out.

While looking at my pictures, and the MFS diagnostic instructions AND the block wiring diagram in my Haynes manual, (check, double check, and triple check!) I noticed my wires are different colors than in the MFS diagnostic sheet. To make a long story short, I think the Lt Blu/org wire on the left, and the pink/yel wire on the right, got crossed. Maybe they got pulled out and the "parts changer" stuck them back in where ever.

I will hook this up tomorrow with jumper wires the correct way, to test my theory. Again, wish me luck!

 

OK, this has gone from bad to worse.
After checking the relays, cleaning and testing the MFS, double checking the wiring and testing the wiper motor, all symptoms seem to point to the GEM. I had my engineer brother look at it, and he agrees.

That was NOT what I was hoping for....

Update 11/11/11:
I have a couple more things to check, but so far all roads lead to the GEM. I have the GEM/fuse box out. I even have the PCB out of the GEM and have done a visual inspection. No obvious signs of damage/moisture/burns/etc.





I have identified which wires connect the GEM to the wiper relays, and I plan to bypass the GEM and install a "wiper/washer switch" (Painless 80173). The relays just have to be grounded for the coils to be triggered. My switch should be here today.


Not cheap, but about 1/3 - 1/4 the price of a GEM (and no trip to a dealer to have it reprogrammed).

I tore the dash apart on the drivers side, which is more than I would expect most "normal" people would do, but this truck had a remote start installed (and done very poorly/sloppy work/bunches of wires tie wrapped, what a mess!) and I wanted to remove that since the previous owner didn't give me a remote. It was already partially disconnected and I wanted to make sure they didn't cause the wiper issues when they installed it.