Hi folks,

Like many others the windows on my '92 convertible started acting up.
They go down but not back up.

At first it was almost like they were sticking or the grease was gummy or cold.
If I pulled up on the window lightly they would go up.

Then they stopped going up at all.

Reading here that these motors are a known problem I had a chance to buy two used motors from a part out car.

I got the door panel off the right side and finally got the motor and gearbox out. Now I need to troubleshoot them. All 4 motors do the same thing.
The motor runs fine in one direction but not in the other.

So here is my question.

Do these motors change direction by reversing polarity, or by providing voltage through one lead to ground for up and voltage through the other lead to ground for down?

When I put a VOM on the two wire leads I get a +12VDC and -12VDC when I activate the switch.

If I put one lead to one connector and the other to ground I get 12 VDC.
I get the same 12VDC on the other connector with the switch in the opposite position.

I seem to be getting good power either way. So which way should these motors work or am I missing something?

 

I am pretty sure they reverse polarity, which is why you had -12 and 12. It still goes to ground somewhere, so if you hook into one side or the other and a ground, you are going to see the power going through it one way or the other.

The deal is pretty much that the window gets assistance going down and resistance going up. Pretty much all window motors I have seen do this get wear in the gearing that allows so much tolerance that they separate.

For the longest I could hit the door with my fist if the window stuck and it would rattle the motor back into place. If you take the panel off what you will probably see is the ring gear walking up and off of the worm gear once a certain level of resistance is met.

There isn't anything wrong or bad about how it is made, it just wears out eventually.

 

thanks,

My gears are fine. No wear noticeable at all. Nothing misaligned or stripping.
With the motor out the windows move up and down with no resistance.

When I have the motor and gear assembly out it turns the gear fine in the down direction but not at all in the up direction.

No clicking like it is energized but not moving, just nothing.

If one motor were doing this and the others working I'd know it was the motor but I have the exact same indications for 4 motors. 2 left and 2 right.

I'm still leaning towards an electrical issue.

I'll pull the switches next and start tracking wires.

I've heard there is a thermal cut-out in this circuit. If so does anyone know where this is located?

 

Try doing a voltage test with motors attached. If there is a bad ground or connection the voltage will drop under load. It can be easy to get a voltage reading without load.

 

On a related topic, if your windows are slow you might try this:



Do not use the cheap lubricants, they tend to contain petroleum. Here are a few better ones, but there are others.

Genuine Shin-Etsu Grease:

Amazon.com: Buying Choices: Honda Genuine Shin-Etsu Grease

3M spray silicone lubricant


hope this helps someone

 

The thermal cut out is a small rectangular thing inside the motor. Pretty easy to spot. I did what "the book" suggested by soldering across the terminals to bypass it, but evidently it was the wear in the gear, as that didn't make it work long.

 

On my '92 the thermal cutout is under the glovebox on the relay tray.
Part no. DAC11334 | Window lift thermal cut-out switch parts from Jaguar Heritage Parts UK




Pic here post 14


https://www.jaguarforums.com/forum/x...roblem-122067/

 

What do the brushes look like??

Also, did you take the panel off and operate it with a load or just perform a visual inspection of the gears?? My gears looked just fine, but if I loaded the assembly it would walk up and off of the worm gear, it would pop back in place if I forced it.