Rear wiper & defroster control

[hear]

Can somebody explain how their rear wiper switch works? I used mine very seldom, and now that I"ve got it unplugged I'm struggling to remember exactly how it did it's thing. Specifically, how did you make the washer squirt, and how did you engage the wiper? Can you control them independently? Does the wiper stop on it's own or will it keep going as long as the switch is engaged?

And on the defroster, there is a timed relay somewhere in the circuit that makes the thing shut off. The FSM doesn't mention it (at least not in the 97 FSM). There's a relay immediately behind the switch, and another one in the PDC. I'm assuming the one at the switch is the timed one, but would love to hear some expertise.

My beautiful new switch panel needs to solve for these functions, just trying to figure out exactly how they work in practice as my starting point.

 

[hear]

To be clear, I'm not looking for analysis of the electrical operation of the switches, just a "what it do when you push it" sort of thing.

 

[CharlesHS]

IF your '97 TJ is the same as the '98 XJ I had... the timer is incorporated into the instrument cluster....
The timer is a black plastic part soldered to the instrument cluster board about the diameter of a nickel and 1/2" tall.
The rear defroster timer went bad on my '98; I bypassed it by running a wire from the bezel switch to the defroster relay, but the defrosters would need to be manually shut off.
The instrument clusters from the TJs are almost the same as XJs and will work on them. I know this because my XJ originally came with idiot lights and no tachometer.

 

[LONGJP2]

Mines not hooked up, but I think it's something like this.
One position (down I think) turns wipers on till turned off, and they will self park.
Other position (up?), momentary switch turns wiper and washer on till released, and they will self park.

 

[lBasket]

Mine you click the switch down for the wiper, and hold it to squirt the water. It squirts as long as you push it. I have a seperate switch for defroster.

The wiper has an alarm built into it to make sure you don't forget to shut it off. JK mine is just squeaky AF no matter what wiper I put on it

 

[hear]

Mine you click the switch down for the wiper, and hold it to squirt the water. It squirts as long as you push it. I have a seperate switch for defroster.

The wiper has an alarm built into it to make sure you don't forget to shut it off. JK mine is just squeaky AF no matter what wiper I put on it

Ok, that sounds like I can just use a DPDT momentary and use the existing wiring (not the plug, obviously). Up for spray, down for wipers. I never keep the wiper running anyway, and I don't know of any switches that a momentary one way and latching the other. That would be perfect. Also LOL @ the wiper alarm.

Still need to figure out the defroster & its timeout feature.

 

[hear]

Here are how my switches operate. The defogger has an audible click and feels solid. The wiper is soft and doesn’t have any defined on/off point, so it’s not at all clear how it controls the wiper & pump. Maybe somebody has a better working example?

I swear the defogger switch has the ability to “cancel” if you lift up on the switch, but I don’t see how that’s possible unless it is able to stay latched down while under power.

Anyone?

 

[lBasket]

Damn, was gonna take a video of how mine work on my 97 but it's switched power and I don't wanna open the garage right now when it's so cold lol!

Pretty sure mine for defrost is press to turn on, press again to turn off early??

Also, is it just me or do videos not work often on this forum? Yours is just audio for me no image

 

[hear]

Damn, was gonna take a video of how mine work on my 97 but it's switched power and I don't wanna open the garage right now when it's so cold lol!

Pretty sure mine for defrost is press to turn on, press again to turn off early??

Also, is it just me or do videos not work often on this forum? Yours is just audio for me no image

The video loads up fine on my iMac screen, I posted from my phone. Seems like it might just be you. ¯\_(ツ)_/¯

 

[lBasket]

The video loads up fine on my iMac screen, I posted from my phone. Seems like it might just be you. ¯\_(ツ)_/¯

Ah, apple and their proprietary media formats... Makes sense

 

[hear]

I finally broke out the wiring diagrams because I'm not sure my wiper switch is working anyway. Sometimes just tracing the circuit is what needs to be done.

The defogger appears to be replaceable with a momentary SPST + a separate LED (I don't care about the icon light). Would love to have an LED tip switch for this but the style I'm familiar with doesn't work like that. They normally just close a circuit and use a separate ground for the LED. That won't work here.

• the icon is lit up by the orange wire on pin 4 when the lights are on
• When pressed, the switch provides momentary ground to the timer relay by connecting pins 1 & 3
  • This turns on the relay in the PDC which:
    • activates the defogger
    • lights up the indicator light on the switch via pin 2

Turning off the defogger isn't obvious from the diagram. The main relay is controlled by a microprocessor on the instrument panel, so I'm guessing that hitting it again opens the circuit to the main relay. That's all black magic up in there.

The wiper is a little more complicated. I don't care about the icon light, so this can be replaced with a DPDT if the circuit can be left open when the switch is off. If the circuit must be grounded when off (i.e. maybe the ground helps the motor park properly?) then it can still be done with a DPDT but the wiper & washer won't be able to work simultaneously (or they must work simultaneously, just wipe will not be an option) w/o using a 2nd switch or a relay.

• the icon is lit up by the orange wire on pin 3 when the lights are on
• Normal state is that the power from the fuse block goes to ground when the switch is off. Not sure why it needs to go to ground, would leaving the circuit open work? Not sure.
• The diagram shows three states for the switch: off/wipe/wash
  • OFF grounds the 12V supply from the fuse box
  • WIPE connects 12V supply from the fuse box to the wiper motor via pin 4
  • WASH does the same as WIPE + connects 12V to the pump motor via pin 2

 

[Rcroane]

Push once on the defroster switch to turn it on. Push it again to turn it off. It will go off automatically after 10 minutes.

 

[hear]

Push once on the defroster switch to turn it on. Push it again to turn it off. It will go off automatically after 10 minutes.

Cool, that’s not how I remember it but good to confirm with actual knowledge. Thanks.