Rear Window Wiring

[spduffee]

Hi All,

I had a chance to work on my key activated rear window switch problem.
The old switch was dried and cracked. My anti-dummy switch (or whatever it's called) was taken out long ago.
I found the always-hot wire, bought a double pole double throw switch and wired it up like this:
There are 6 terminals.
Always hot to the two outer opposite terminals joined.
Opposite two are grounds.
The two middle ones go to the motor, one each. One is spliced into motor-wire 1, the other to motor-wire 2.
It works and so does my dash switch.
My new new rear switch has issues I don't understand.
It goes 1/2 the speed of when I use the dash switch.
With engine off it works but then stops, like it ran out of juice. With the engine on I can hear the strain on my alternator when I hit the switch.
Using the dash switch it goes up and down just fine, as it did before, which is amazing considering I worked on it...
Can anyone explain what is happening and what I can do to fix it? Or will it stay that way?
Thank you!

[SJTD]

A picher is worth a thousand words. Would help if you could draw what you have or at least post a link to the switch schematic.

The if I remember correctly the power goes through both switches regardless of which is actuated so it should go the same speed regardless of which is used. Sounds like it's shorting when the rear switch is used and loading the alternator.

I'd quit using it until you get it figgered out. Aint going to get any better by using it and may be doing damage.

[spduffee]

Here is a sketch of what I did.
I thought, too, better not use it anymore until I figured it out. Same instinctive feeling I had at puberty and in infantry training....
From schematics the only real difference, I think, is that I hacked into to motor wires vs. them going through my new switch.
If the ground were not good enough it wouldn't work at all, right? Or can a crappy ground affect how it works?
Thanks for your help!

[SJTD]

Took a look at your picher. If I remember correctly, in the off positions the front switch grounds both wires and the rear passes both wires straight through. Actuating the front powers one and grounds the other. So your front would still work as you've found and would be ok to keep doing.

Actuating the old rear switch disconnects one wire from the front and puts the 12v to it. The other leg still goes to through to ground through the front.

But when you actuate what you've got you put the willy to one wire which powers the motor but also gets grounded through the front.

I think that's what's happening anyway. I'll try to take another look it and the wiring diagram later to make sure and see if I can figger out how to easily make it work with that switch. Could do it with relays like the kit Serehill used to sell and a few other guys are making.

I think BJ's sells the proper switch but it's a bit more than what you have.

[spduffee]

Thank you.
That switch at BJ's is what I have. I just don't have the machined block spacer used to hold it in the switch carriage. I'll work that out later, once the thing works.
I think I need to run the wires through my switch following the original schematic.

[SJTD]

I see BJ's has discontinued the original style and sells a different one plus a jumper. And the mount and instructions. I take it you don't have them since you don't have the mount?

Haven't had a chance to dig into this other than to find the pin-out for a common DPDT center off switch that has the two center terminals being the commons, NO's on one end and NC's on the other. Does yours have a picher on the side showing that?

[SJTD]

I can't make it work with a DPDT center off switch without relays. Not saying it can't be done, just that I'm not seeing it. Needs to make contact in the center position too. I'm not sure what such a switch would be called. 2 Pole On-On-On? Haven't found one with a bit of searching.

I assume BJ's is selling the right switch but I need a diagram.

[Tripwire]

i might have the complete switch and mounting bracket somewhere, pm me if interested - may even have a tailgate wiring harness....i threw a ton of stuff away though

steve

[spduffee]

Tripwire,
I just sent a pm to you regarding your parts.

Last night I reversed everything back to the way it was.
What I now noticed is 1) my gas gauge reads incorrectly and 2) my in dash ammeter reads lower than before.
The gas gauge was working fine until I started monkeying with the rear window switch. It read nearly empty so I stopped to get gas. It usually takes 13-15 gal. It stopped at 7. I thought maybe it stopped mistakingly but no, it was full. Reads 1/2, then 3/4 depending...
The ammeter reads just above 12. It was showing 14 or so. I checked at the battery and it reads 14.5 on the multimeter when running.
So, looks like something did go screwy when I was using my new switch.
I'll pull the sending unit and test it.
Weird.

[wiley-moeracing]

sounds like your grounding out in the rear area from your wiring.

[nograin]

Tripwire,
What I now noticed is 1) my gas gauge reads incorrectly and 2) my in dash ammeter reads lower than before.
The gas gauge was working fine until I started monkeying with the rear window switch. It read nearly empty so I stopped to get gas. It usually takes 13-15 gal. It stopped at 7. I thought maybe it stopped mistakingly but no, it was full. Reads 1/2, then 3/4 depending...
The ammeter reads just above 12. It was showing 14 or so. I checked at the battery and it reads 14.5 on the multimeter when running.
So, looks like something did go screwy when I was using my new switch.
I'll pull the sending unit and test it.
Weird.

That's not an ammeter. That's a voltmeter.
It should zero when the key is off.
When the key if off, and nothing is on, voltage across the battery should be around 12.7.
With the engine running, the voltage at the alternator should be 14 - 14.5 depending on year and air temperature.
The voltage at the battery should be close to the same as the voltage at the alternator.
The voltage on a dash gage could be a little less or a little more (but less than the alternator of course. It depends on where its wired in, and how much current is flowing through the circuits up to that connection.

An '86 up SJ is wired differently than an '85 down.

As far as the tailgate window wiring, if you want I can post the factory wiring as I found it in my '85.