Rear wiper won't "park" itself

[br1anstorm]

The rear wiper on my 1993 XJ has started misbehaving.

The wash/wipe function continues to work as normal. So the wiper-motor is obviously working (as is the pump for the fluid).

In the past, when I switch it to wipe only, the rear wiper makes two or three sweeps of the glass, then parks itself back in the horizontal position..... then after a short interval, it wipes the same way again. This is the normal operation. It always works on an intermittent setting.

Now, on wipe only, it maybe gets half-way, or does one sweep, then stops (often vertically!). It does not park itself back down. After a short interval, it moves again, but still only half a sweep or so, and doesn't park horizontally.

Now..... I'm reckoning that there is a relay somewhere which controls the intermittent wipe-frequency; and that is still working. But I guess there must be something else - is it in the wiper-motor? - that should ensure that it automatically "parks" horizontally at the end of its wipe.

Am I right? If so, what might be causing the wiper not to return to its 'park' position but stop part way? Where do I look, and how do I fix it? I have read in the forum (and seen a youtube clip) which suggests that water/corrosion down the shaft tends to make the wiper movement stiff and can eventually strip the gears.

But if the wiper motor shaft or gears were rusting, or the grease had dried out, making the wiper stop instead of returning to its park position, then why does it work perfectly normally when in the wash/wipe mode?

I haven't yet tried to remove and strip down the motor, because I'm not yet sure whether I should be looking there or at something electrical elsewhere.

Any ideas?

 

[jeremyj]

My original motor quit working a while back, so I replaced with with a rebuilt one from Autozone. Less than a year later, the "new" one is doing exactly what you're describing. Rather than tearing into it, I was just planning to replace it with a new one from somewhere else.

 

[Ecomike]

Partial answer, too much friction with no wash solution-water to lube it. My front one does that recently.

 

[CarbonXJ]

I believe inside the motor is a "track" of sorts that tells the wiper it's intermittent time interval and path. It gets worn down the wiper acts like you are describing. My Expedition did the same thing, except it actually has a "park" position that is off the glass, and raises onto the glass for wiping until you turn it off, then it parks. When it acted up, it would not park, and thus I could not open the glass. I replaced the motor, and took apart the original, and saw the "tracks" that it could follow. I cleaned it up and bent around some tabs, and for kicks, tried it out - it worked just like new. NOw I have a back up.

 

[ParadiseXJ]

It's possible that the wiper arm (where it attaches to the motor stud) is either loose or the stud is partially stripped out. Grab a screwdriver, pry the "tab" out, pull off the arm. Check out the connection there, if the knurl/spline is stripped or there are metal filings in the hole, or on the stud.

You should be able to clean off the stud, clean out the hole, spray it out with some brake cleaner, then put it back on with the stud AND the arm at the "parked" position. It might actually help to put a light coat of lithium (or similar) grease on the stud so you can push it on all the way, then make sure the tab is fully engaged.

My opinion based on my own experience.

 

[br1anstorm]

An update - and a request - after doing some further work on this.

I checked the shaft and splines, and the socket of the wiper arm. All good - no sign of wear or slackness. No pronblem of friction across the glass.

So I took off the inner trim from the rear hatch, and removed the wiper motor to check and test it. Removal is pretty straightforward. On the bench I took off the panel covering the motor gears, and although after 23 years the grease had dried out a bit, the plastic gear wheel teeth and the metal cogs were all still in good shape with no trace of water or rust. So no water-ingress down the shaft.

Testing the motor confirmed that it was OK too. The problem was evidently with the relay which is mounted "piggy-back" to the side of the motor. It would only activate for a second or two before cutting out - so not long enough for a complete "sweep" of the wiper.

By fortunate coincidence I happened to have a spare motor, complete with relay, in a hatch salvaged years ago from a scrapyard. I swapped them over, and this spare motor and relay work fine. So my immediate problem is solved.

But it seems a shame to throw the original motor out just because the relay is bad. I would like to revive or repair it. The motor etc is all good. All I need to do is replace the relay (which slides off a metal mounting on the side of the motor). It is made by Valeo. The part number is 73809802. The weird thing is - I cannot find that relay anywhere on the internet, or in any catalogue. Not even on Valeo's own website. The relay is a little unusual. Its five connector tabs are all in a straight row: the relay slots into a socket which is fixed to the mounting. See these photos for details:






So my question is..... does anyone know either a source for this particular Valeo relay, or an equivalent compatible part from another manufacturer? I have not yet found any cross-reference to, for example, a Bosch, Hella or Nagares relay which might serve as a replacement.

 

[Ecomike]

Try searching "relay 73809802 12V"

This looks close, but the second # string may be something about the amps or timer sequence and does not match, at least it may lead you to more hits

http://www.aliexpress.com/store/product/For-Valeo-relay-12V-73809802/1048167_32356308503.html

http://www.alibaba.com/product-detail/For-Valeo-relay-12V-73809802_60315913848.html

Interesting info thanks for sharing!!! I need to fix 5 of these someday that are dead. Never had or seen one work yet.

 

[br1anstorm]

Thanks, Ecomike - I had googled the ref number already and got the same sort of results.

Those two sites you linked to are Chinese suppliers ..... and I have to say I'm not sure whether what they are offering knock-off copies of the Valeo relay, or perhaps just the plastic casing! Either way, I'm not inclined to try to order from there.

The puzzling question is - if Jeep are still installing wiper motors with a time-delay relay, then they must be sourcing the relays from somewhere (and surely not China?). Can't figure out why Valeo don't list that relay as one of their products.

Just as well I had a complete spare motor with its relay from the scrapyard.....

 

[xjtrailrider]

Junk yard, about $15 for the whole rear wiper unit. I just bought one for my 90 and eliminated the delay unit and made it a "on or off" rear wiper like the 90 originally had. It still parks itself as normal so the delay unit isn't whats causing yours not to park.

 

[CarbonXJ]

An update - and a request - after doing some further work on this.

Testing the motor confirmed that it was OK too. The problem was evidently with the relay which is mounted "piggy-back" to the side of the motor. It would only activate for a second or two before cutting out - so not long enough for a complete "sweep" of the wiper.

Junk yard, about $15 for the whole rear wiper unit. I just bought one for my 90 and eliminated the delay unit and made it a "on or off" rear wiper like the 90 originally had. It still parks itself as normal so the delay unit isn't what's causing yours not to park.

The delay unit is causing it if the relay fails and cuts power in the middle of the stroke.