**RE-FIXED with Videos** Rear wiper won't turn off

greiswig

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So, weirdly, the pink/grey power line on the diagram splits into two pins. So, looks like both pink/grey power line pins would have power all the time. I think you would need to probe specifically that purple/grey pin to tell.
Interesting! That's not typical for the way I've seen relays done, but...it's a Land Rover.
 

Tbh1981

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As per the title, today when I closed my passenger door, the rear wiper started running again. I can only assume that when the door closed, a wire was re-shorted to power. However, if you watch the videos, you'll see that electricity seems to be only going to the relay box where it is supposed to be going... Again, I am at a loss.

There are 2 videos because I accidentally stopped recording in the middle of testing the problem.

Also, there will be a third video showing the removal of the CJB, the condition of the pins in the back, and all the wired connectors under the dash. Just waiting for that to upload to the computer so I can put it on Youtube.

Vid 1

Vid 2
 

Tbh1981

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UK wiring. Don't fight it.
I considered just not having a rear wiper, and leaving the relay unplugged, but where I live, we're about 2 months away from crazy snow season, and w/o a rear wiper I'd not see anything behind me again until May 2022.
 

jlglr4

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Bizarre. Looking back at the circuit diagram, I see only two ways that wiper motor can energize: (1) signal voltage to the purple/grey wire (“J” in diagram), which turns on the relay normally, (2) the black ground going into the relay (connector C2937S4) crossed with power and became a voltage source.

There could also be a problem in the park circuit, but I don’t think that could energize the wiper motor. The park circuit only delays de-energizing the circuit until the wiper is in the right position. In other words, even if the park circuit was faulty, you would still need to see voltage at that purple/grey wire or the black ground wire going into the relay, right?

If it were me, I would probably do the following: (1) plug the relay back in - make sure the motor is still engergizing, (2) once the wiper motor is moving again, remove the relay carefully (or maybe you can back-probe the connector?) and separately probe the grey/purple and black ground coming into the connector to see if there is voltage, (3) get a probe to stay securely in that purple/grey cavity, and then move the harness around in the back - see if any voltage lights up - same with black ground cavity. (2) keep that probe in the purple/grey cavity and see if there’s voltage while moving the CJB around in the passenger area (maybe use the max/min function on the voltmeter, or just have a helper monitor the voltage).

Any other thoughts here welcome.
 

Tbh1981

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OK everybody, I'm sharing 4 videos: 1 shows behind the CJB, 2 and 3 will show the source of the short that I found and repaired, and the fourth shows the wiper functioning normally again.

All told, I'd say this was near 10 hours of diagnosing (yesterday and today) as well as 2 hours to do the repair and re-assemble everything. I don't know what shop fees are in your area, but I'd say this fix saved me about $1500, if I include the time to repair the sunroof drain as well (where this all started for me.)

Watch the vids, maybe it will help you in the future. But, until my wiper malfunctions again, or I get around to the water pump/coolant manifold service, it's been a slice.

Thank you all for your advice and suggestions, especially @jlglr4: without the wiring diagrams and your explanations, I would have been lost.

Behind the CJB:

Found the short? 1:

Found the short 2:


The 4th vid is still processing. Will post later
 

f1racer328

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Wow. Funny how all of these issues surfaced as soon as you started messing around with the sunroof drains...

Glad you got it fixed this time around. The thought of mouse damage crossed my mind, but I kind of wrote it off in my head. Just thought you had some relays going wild.

Glad to see it's fixed! Hope you can keep enjoying your Discovery.
 

jlglr4

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That’s great news. Wish I could make sense of how those wires being chewed ended up turning your rear wiper on (and not causing a whole host of other problems), but I simply can’t. I can find them on the diagram (based on the colors you gave), but I can’t trace them to any logical conclusion for this fault. For sure, though, a great find. That rodent damage was destined to cause many headaches beyond just the wiper in the future.
 

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