Wiring window switch to 12v relay

[Philippe M. Ruel]

My concern is the switch center post using direct hot. Would that bypass the relay, thereby negating it. Or is the switch protected through the grounds in relay?

The direct hot on the switch will not bypass the relay, as it is part of the low amperage circuit, together with the relay coils. This circuit includes the red and white wires on your schematics.

The high amperage circuit includes the relay switches and the window motor (green and black wires).



Remember, in a car, only one "hot" - the battery positive post - feeds such low-amp items as instrument panel lights, and such hi-amp items as headlights or starter.

[52Cadillac]

Great. Appreciate the explanation. I'll wire her up soon.
Try to get everything on my wishlist completed before the Boston GN.
The power top will be another project. A company online makes a wiring harness for all this however it's for the Hydra/electric system previously in place.
Thanks, Mike

[76eldo]

The rear quarter windows and the top motor are all controlled by switches and relays on my Hess & Eisenhardt 80 Eldo.

There are two relays for each window, that's why you seem to have two hot wires.  One for up and one for down.  Not one relay.

I had to troubleshoot the wiring when all of it stopped working.

You should be able to get standard Bosch automotive relays.  The breaker has two posts with nuts to secure the wires on it.  there is a feed side (batt) and a load side (window).

Using a test light on all of this will help.

Brian

[52Cadillac]

Ok, thanks Brian.

Couple questions. Got her all wired works great, except either rear switch will operate both windows at the same time. Do I need separate relays for each switch? I've got both wired to the one relay?

I also installed a 20 amp in line fuse on the main hot leading to relay and switches. Is this sufficient to protect the relay and the window actuators?

Is there a way to slow down the speed of the window motors? They go up quickly. Original speed I'm sure was a lot slower.

Lastly I pulled the drivers 4 window switch, and it wasn't clear to me on how to wire to the rear switches? The drivers window switch has the main hot on one end. Then 2 posts for each window.

[Philippe M. Ruel]

either rear switch will operate both windows at the same time. Do I need separate relays for each switch?

Yes, you do .

I also installed a 20 amp in line fuse on the main hot leading to relay and switches. Is this sufficient to protect the relay and the window actuators?

Try raising all four windows at the same time (using driver's switch or calling a couple of friends). If it blows the fuse, it means the fuse is not sufficient.
I would rather use a 25 amp circuit breaker, or even one circuit breaker on each motor.
A fuse will easily blow, should someone try to raise a window that is already raised.

Is there a way to slow down the speed of the window motors? They go up quickly. Original speed I'm sure was a lot slower.

The standard solution to this is to add resistors on feed lines, one for each motor. The question is, which value to these resistors ? You can proceed with a first test by using a headlamp (about 3-4 Ohm for a standard 12V sealed beam) as a resistor, then you will know if you need a higher or a lower value.

Lastly I pulled the drivers 4 window switch, and it wasn't clear to me on how to wire to the rear switches? The drivers window switch has the main hot on one end. Then 2 posts for each window.

You need to modify the main switch the way you modified the other ones, and keep the original wiring (each pair of switches in parallel).

[52Cadillac]

Thanks Philippe,
Got it.
Only reason for the inline fuse is I'm not sure what circuit breaker to use. Bruce first suggested it, and I wasn't able to locate any. I will try to locate again. Does anyone know where to purchase, and what brand and type.
Thanks, Mike