98 Passport - Rear wiper acting weird

12-15-2010, 09:38 PM
Hello all . . . haven't posted here in awhile. Haven't had any issues until today. Hoping someone has some thoughts.

Left work tonight and it was rainy, so I hit the rear wiper switch. The wiper started and cleared off the window, so I hit the button again (which should have turned it off after a couple more swipes). But the wiper kept moving for several minutes even though the switch was off. Eventually it stopped, but it stopped in the middle of the window--not at the bottom like it should.

I thought that was a little weird but figured maybe it was just a glitch. So I turned the wiper on again and it did the same thing. Tried that a few more times. Eventually with the switch off, it stops but it stops while it's still on the glass (so the tailgate won't open if I need to get something out when stopped).

The other weird thing is that I has stopped off to do some shopping onthe way home. The wiper was not running and the switch was off when I turned off the car. When I came back outside and started the car . . . the wiper started--even though the switch was off.

Anyone have any ideas on what the cause of this might be and how it might be addressed? It's like my rear wiper suddenly became possesed today. It was working fine up until I left work tonight.

12-15-2010, 11:13 PM

12-15-2010, 11:35 PM
Thanks, Ryan! I will check those posts out. I went ahead and ordered some relays . . . according to Mouser they only had 11 left and they are being EOL'd, so not sure how long they would be available. Figured it would be good to get a few of them just in case.

Sounds like I'll need to learn how to solder :iceslolan

12-25-2010, 06:38 PM
OK . . . here's the update. Kids were playing with Xmas presents and wife took a long nap, so I decided to try and tackle the relay issue. I got the correct control module pulled out and got out my soldering/desoldering stuff (just bought them the other day--have NEVER done any soldering before) and then I went to work.

Below is the module from my 98 Passport. What I found was that the smaller relay is the main On/Off for the rear wiper, which is giving me issues. I replaced it first with a brand new relay from Mouser. No change. Still operates the same screwed up way. On the off chance that it might be related to one of the other relays, I went ahead and replaced the three circled below as well since I ordered replacements from Mouser too. Again . . . nothing. Still malfunctioning as described in the OP.


The only other relay left is one that I do not have a replacement for, it's an entirely different kid than the others, naturally. But I don't think it's the problem. The smaller one (the one I replaced first) is clearly the one turning the rear wiper on and off. I hear and feel it clicking when this is happening.

So . . . I'm wondering if I might just have a bad dashboard switch????? Does anyone think that might be the issue--would the switch itself cause the rear wiper to have a mind of its own for turning on and off and stopping in different places on the rear window?

If it is the switch--how do you get to it? Does the smaller dashboard "panel" come off somehow (without taking off the whole dash)?


12-25-2010, 07:59 PM
They should just pull out the front. I've installed a fog light switch in its normal location and it just pushed right in and I can grab onto the top of it to pull it right out.

12-25-2010, 08:19 PM
Oh, cool . . . that would make it a lot easier. I think I'll order a new switch or see if I can find one at a junkyard and try it out. Trying to DIY this one as the truck has 175k on it and I really don't want to spend the $$ at a repair shop chasing it down. Getting to the point where I have to consider diminishing returns, as much as I love my Passport.

Thanks, Ryan . . . Merry Christmas!

12-29-2010, 01:25 PM
Latest update . . . I ordered a new Rear Wiper switch from St. Charles, so I will probably give that a shot once it arrives. Should have it in a few days.

BUT . . . I went out to a pick-n-pull place in Denver this morning and they had just gotten in a 2000 Rodeo today. I found it in the yard and took out the rear wiper motor, the alarm control module and a few other things (including the rear wiper switch--just in case I ever need another). I have not tested out the motor, but it only cost me about $17 so it's a low-cost thing to see if that is part of the wiper problem.

On the alarm control module . . . the one I pulled from the Rodeo looks slightly different than the one I have in my 98 Passport. Looks like maybe one of the relays is just a different kind or in a differnet spot. Does it HAVE to be the exact same alarm control module for the 98, or does anyone think that it should function the same if I swap it out?

I replaced the relays on mine and it didn't fix the issue--so I really don't think it's the control module. But while I was pulling parts I figured for another $15 grabbing the alarm control module from the junker was a no-brainer.

Planning on trying the wiper motor later today!

12-29-2010, 02:34 PM
Well . . . I answered a couple of my own questions. Just got back from the garage.

- It's not the Rear Wiper Motor: I swapped out my motor with the one I snagged from the pick-n-pull and they both do the same thing. So unless both are bad in exactly the same way, I believe I have my answer that the motor isn't the issue.

- The Alarm Control Module is Different: I disconnected my alarm control module and compared it to the pick-n-pull part. The circuit board is a little different as far as design/relays/model# . . . but the big thing is that the connectors are different. The one from the 2000 Rodeo won't even plug into my 98 Passport if I wanted to try it.

So I guess that leaves me with the rear wiper switch itself as a strong possibility. I'll wait til I get the new one delivered and try that one out. I don't want to take apart the dash to take a chance on the junkyard one I picked up this morning. The only other thing I can think of is that maybe it's the ONE relay that I did not change out that could be causing the issue, or maybe a short or something somewhere. I highly doubt it's that other relay though.

If the switch doesn't work, then maybe I'll look to swap out the other relay--I'll have to order one as it was different from the other 2. After that, I don't think I'll mess around with it anymore. I'll just unplug the rear wiper motor and wipe off the window as needed.

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