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Rear wiper delay

ghettocruiser

NAXJA Forum User
Location
Norristown, PA
Hey everyone. I have a question about the rear wiper on my 94 Sport. I would love to use it more often, but I find that if I just leave it on, it will wipe too frequently. Is there anyway to make this "delay" adjustable? Maybe a control from a newer XJ or another vehicle? I guess there is probably a way to add a variable resistor someplace, and I would do it if I had instructions. Any ideas would be great. Thanks.

Justin
 
I bet that you use one of those after market wiper delays. NAPA, Auto Zone, etc has them for about $20 and they come with instructions and wiring diagrams. I would wire it in some where close to the factory rear wiper switch.
 
Hmm...I looked around at work (Autozone) and couldnt find any universal switch. I think Ive seen them, but who knows. So I paged through the Wells book and ordered two wiper switches. One from a chevy and one from a pontiac. One is a slide, and one is rotary deal. I looked at the schematics for the wiring...I should be able to make something work. We'll see. Im starting to think I need to modify more than just the switch. Like I think it needs a delay board back at the wiper. Or something to that effect. Oh well...Ill mess with it I guess.

Justin
 
The delay circuit is built into the wiper motor. I've never had one apart, so I don't know how easy it would be to modify. Since this motor has two terminals, one for normal (built-in delay) and one for wash (constant), you might do well just to disconnect the normal, and connect your wipe switch through an external delay circuit to the constant terminal. If you're adventurous, you might still see if you can figure out a way to tap a variable resistor into the built-in delay circuitry, but that would require a new pair of wires to wherever the control is located, unless you can settle on a single delay value and hard-wire it in place.

It occurs to me that if you use the constant terminal, you might also have to put a couple of diodes in the circuit to avoid feeding back to the washer pump when you run, and to avoid feeding back into the delay circuit when you wash.
 
I don't know anything about wiring, but it strikes me that XJs already have a variable delay unit on the front wipers - could one be rigged (with an appropriate knob) to work for the rear too?
 
Chancer said:
I don't know anything about wiring, but it strikes me that XJs already have a variable delay unit on the front wipers - could one be rigged (with an appropriate knob) to work for the rear too?

It probably could, and I think that's what Ghettocruiser is on the trail of. The variable delay on the front consists, basically, of a variable resistor in the signal stalk, and a delay unit that is inserted into the circuit of a regular wiper motor. You could easily do this with an older XJ whose wiper has no built-in delay, but the newer ones have a delay unit built into the motor itself, and use a separate connection on the motor for continuous running when the washer is on. So an external delay may be a challenge.
 
Hey guys. Glad to hear from a couple of you on this. I did a little looking into this and Im not sure Im going to get any results just using another switch. I havent had a chance to look at our 97 Grand, but I know its got a slider with an adjustable delay for the rear wiper. So...I found a switch on ebay pretty cheap. Picked that up. Now...I guess its just a matter of finding out about the delay module on the grand. When it boils down, the wiper motor should be able to operate with a single power source. As should the washer cycle. So as long as I can get a delay system to operate outside of the vehicle, I can just "add" the wiper motor. I should be able to make the ZJ wiper switch fit because its basically the same size and all. Plus it has the OD and Defroster switches...I can use those for something Im sure. The other two switches I ordered at work will easliy fit too, but I figured its a jeep...why not try to use jeep stuff. Anymore ideas..definetly shoot them my way. Ill keep you all updated. Might be a nice mod if it turns out to be easy. Later.

Justin
 
Let us know what works i'm interested too. I added a rear wiper washer to my 92 but would like intermit. Saw a switch j.c.whitney i'll check.
 
frankenjeep said:
I havent had a chance to look at our 97 Grand, but I know its got a slider with an adjustable delay for the rear wiper.

i wonder if this would work on a 99 xj??

I don't believe it will as a drop-in - you'll probably need to figure out which part of the XJ wiper motor assembly provides the delay, disable it, wire the switch in-line to replace the existing one, and build any necessary inline current regulators to prevent the whole thing burning out. It may actually be easier to swap out the XJ wiper motor for the WJ one. How does the WJ switch handle activating the rear washer compared to the XJ? It's been a long time since I've seen one, but it seems like that may be an issue to consider.

Of course, this is entirely based on speculation - I've never tried something like this, but the idea has crossed my mind. The approximately three-second delay between wipes *never* seems to fit the weather conditions, and flipping it on and off by hand is pretty tedious.
 
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