J truck wiper switch

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Topic author
arlingtonslim
Posts: 12
Joined: Tue Jun 02, 2015 3:45 am

J truck wiper switch

Post by arlingtonslim »

85 Jeep J20

I only have one wiper speed. wiper motor tests good hooked up to a battery and has more than one speed (I forget how many)

Using a voltmeter if I go to ground and to the body of the switch or the wire that comes off the switch I get 8-10.5V with just the key and switch on.

Internally shorted switch?

Bought a new one and it does the same. I don't see why the switch body would be charged as it goes all to hell if you touch the dash (as you might expect)

New switch bad too?

I don't see a Intermittent relay box in between the plug from the harness and the switch. Could it be the wrong switch?
85 J20/360 amc
91.5 Dodge 250 Cummins intercooled 4X4
79 International Scout II with a P-Pump 95 5.9 Cummins.

twisted frame
Posts: 637
Joined: Wed Mar 27, 2013 9:41 am
Location: Massachusetts

Re: J truck wiper switch

Post by twisted frame »

I'm fuzzy on 85 FSJs. I think you must have the final style dash with the 3 rectangular gauge pods as opposed to the mid-70s to early 80s 3 circle gauge pods, is that right? Here's a pic that points out the location of the intermittent wiper relay. Does this match what you have?
https://goo.gl/images/akQEbp
73 J4000. 360, MC 2100, T18A, D20, stock closed knuckle Dana 44 front, 60-2 rear. Warn Lock-O-Matics, Warn/Belleview electric winch, true duals with glasspacks, old-school front diff skid plate, used 265 Toyos on 16" AR wheels.

Topic author
arlingtonslim
Posts: 12
Joined: Tue Jun 02, 2015 3:45 am

Re: J truck wiper switch

Post by arlingtonslim »

My 85 was from Michigan and the cab and frame were a total loss. I lifted the bed off to look at the frame and the back of the frame fell off! I'm actually using a 78 cab and a different frame (luckily I live near Jake and Jackie), but re-used the full 85 harness, switches, converted the firewall for the newer 85 wiper motor, and used the full 85 drive train/360 AMC. I'm using the gauge cluster that was in the 85 truck when I bought it and it's 3 round gauges, not square. The wiper switch uses the half moon shaped plug. Pictures Ive seen look like there should be a relay that plugs in between the harness plug and the wiper switch. I don't see that on my truck, but I do think my switch is for intermittent. I've seen pictures of the rectangular relay box like I think your picture is showing and I don't think I have one of those. I'll look again later this morning. It could be hiding somewhere. It's been last year since I put the harness in, so I don't really remember at this point.

I'm half wondering if I have a hot wire shorting out somewhere on the truck and that's what I read with the ohm meter between the dash ground and the switch body. Could be anywhere if that's the case. I've been reading on the internet, but I always wind up with a problem no one else has ever had...ha. I can probably figure out how to wire in a toggle switch for wipers, but I'd rather not if possible. I may have 2 problems as I still only have one wiper speed which is the fast one. I can leave the switch hanging under the dash not touching anything and the one speed works fine.
85 J20/360 amc
91.5 Dodge 250 Cummins intercooled 4X4
79 International Scout II with a P-Pump 95 5.9 Cummins.

Topic author
arlingtonslim
Posts: 12
Joined: Tue Jun 02, 2015 3:45 am

Re: J truck wiper switch

Post by arlingtonslim »

I looked around and still didn't find a relay anywhere. Would not having a relay with a intermittent switch cause my problems? I'm thinking the relay should look like the 2nd picture down in this old thread.

http://www.ifsja.org/forums/vb/showthread.php?t=163016

I did run a jumper cable straight from the battery and checked between the switch and the battery ground and it still reads voltage, so it's the switch body that is hot.
85 J20/360 amc
91.5 Dodge 250 Cummins intercooled 4X4
79 International Scout II with a P-Pump 95 5.9 Cummins.

twisted frame
Posts: 637
Joined: Wed Mar 27, 2013 9:41 am
Location: Massachusetts

Re: J truck wiper switch

Post by twisted frame »

arlingtonslim wrote:I looked around and still didn't find a relay anywhere. Would not having a relay with a intermittent switch cause my problems? I'm thinking the relay should look like the 2nd picture down in this old thread.

http://www.ifsja.org/forums/vb/showthread.php?t=163016
I'm not totally sure but I'm leaning towards yes. Wish I could help more but I'll need to leave it to the electrical pros!
73 J4000. 360, MC 2100, T18A, D20, stock closed knuckle Dana 44 front, 60-2 rear. Warn Lock-O-Matics, Warn/Belleview electric winch, true duals with glasspacks, old-school front diff skid plate, used 265 Toyos on 16" AR wheels.

Topic author
arlingtonslim
Posts: 12
Joined: Tue Jun 02, 2015 3:45 am

Re: J truck wiper switch

Post by arlingtonslim »

Finally got back on my J20 project. I've been driving it around, but just when it's pretty clear. I'm getting it ready to use this winter while I decommission my old dodge cummins for repairs. I found a guy on Ebay selling a intermittent wiper switch and control box/harness from a 70's bronco. I bought it and plug and play wipers are back online. I suppose buying a non-intermittent switch would have also fixed my problem. I re-used my jeep switch so the length would be the same in the dash. I just had a intermittent switch, but was missing the control box for it. Now on to the fan motor.........
85 J20/360 amc
91.5 Dodge 250 Cummins intercooled 4X4
79 International Scout II with a P-Pump 95 5.9 Cummins.
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