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Discussion Starter · #1 ·
Help! Any ideas on the power window for my `1994 Esprit S4? The passenger window quit working. I pulled the door panel and the relays were clicking when I tried the switch. So, I removed the window motor.

On some earlier Esprits, the magnets in the motor had come unglued to the case. In my car, these are held in by wire clips and all looked well. I cleaned it all up, and tested it on a car battery – runs fine. Reverse the positive and negative, and the motor reverses, working fine in both directions.

I plugged it back in and nothing…. I checked the voltage at the wire that plugs into the motor and it id 12 volt positive when I hit the up switch, and 12 volt negative when I hit the down switch (or the other way around, as I am not certain which terminal is up/down. So, I checked the motor again on the battery and it works fine. I actually tested it with just a single wire (so about 100 gauge), thinking that perhaps the wiring to the motor was showing 12 volts, but did not have enough amps. Anyway, the motor works fine with just one fine wire providing power, but will not run when clipped into the car wiring harness.

Any ideas? Thanks for any guidance…

Mitch
 

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I would start by swapping, or preferably replacing, the relays.
 

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Discussion Starter · #4 ·
thanks guys.... i wonder if the relay(s) is bad, why do i get the 12 volt reading at the connecter that goes to the motor?
 

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The relays switch both leads to the motor, so one could be providing 12V but the other may not be supplying ground. The two leads are floating, when the motor is commanded up the 12V is applied to one lead and ground to the other, for down the two leads are reversed.
 

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Make sure you do the guides, too. They are cheap and probably broken, putting a big load on the motors & electronics. I wrote it up about a year ago.
 

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Discussion Starter · #7 ·
I am baffled...

I replaced all four relays (drivers and passenger side, even though the driver side is working). I removed, cleaned and tightened the ground wires inside the door.

I still get 12 volt (negative or positive - depending on if I push the up or down button) at the connector at the end of the wiring harness that goes to the motor. I am only using those two connectors to get the reading - not a separate ground or power. So, that seems fine.

The motor will run when connected to a battery, and it draws very little current when it is running free. It will run with just a single strand of speaker wire, so it does not take much current for it to run.

However, when I plug it into the harness (not installed in the door, just connected to the wiring harness) it will not run. How can I be getting the 12 volt at the plug...and have a motor that runs on 12 volts...but not have the motor run when plugged in?
 

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when I plug it into the harness (not installed in the door, just connected to the wiring harness) it will not run.
Does the motor case need to be grounded?????
 

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Discussion Starter · #9 ·
Does the motor case need to be grounded?????
No...you can hold the motor in your hand and connect the two wires to the positive and negative of a battery and it runs.

I don't understand how it can have 12 volts (positive and negative) at the plug, but not run when plugged in....

I do appreciate the suggestions and welcome any other ideas!
 

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The only logical explanation is s defect in the plug. It may be a little radical but patch a wire around the plug and see if the switch works - it may be a question of the ability of the switch to deliver sufficient amperage to the motor. You may be getting 12V but not enough current past the switch. Directly running it successfully off a battery suggests that to me.
 

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Perhaps the body of the motor is shorting through the mount of the door. Also, check the voltage at the connector while the motor is connected.
 

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Discussion Starter · #12 ·
Thanks for all the guidance.... I ended up changing the relays, cleaning the ground wires, cleaning every connector that I could find (switches, relays, motor, etc.). I cleaned the fuse connections. I took out what I think is the "window motor voltage regulator" and cleaned that.

Actually, if anyone could tell me what the window motor voltage regulator does and where it is (to make sure I got the right one), I would appreciate that.

Anyway, after all this cleaning and replacing...the motor worked! I put it up and down about 10 times. Then, I put it all back together and tried it a few more times. All good......until I went out for a drive and put the window down...then back up. Tried to put it down again and it will not do anything!!! :-(

Any guidance on the window voltage regulator would be appreciated.
 

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Resurrecting this beauty

Were you able to resolve this?

When I put power to the window motor plug window works great. I hear and feel the relays clicking.

The PO said he had the window worked on several times. The motor and actuator assembly looks new?

My car is a 94.

I swapped driver to passenger switch, did not help. Drivers window works well

I will try replacing the relays
 

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Tried installing a jumper wire between terminal 87 and 30 for both relays...big spark but still not work. I checked the fuse. Did not blow.

So odd. Direct voltage to the motor plug operates window up and down. Gotta be tired relays - take the relays out of the system- no luck.

Gotta be a flaky motor?

swapped switches with the working drivers side no luck.

I guess next move is to take out the motor and see what it looks like.
 

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Tried installing a jumper wire between terminal 87 and 30 for both relays...big spark but still not work. I checked the fuse. Did not blow.

So odd. Direct voltage to the motor plug operates window up and down. Gotta be tired relays - take the relays out of the system- no luck.

Gotta be a flaky motor?

swapped switches with the working drivers side no luck.

I guess next move is to take out the motor and see what it looks like.
Remove both door panels and the small plastic ocevr hiding the S4 relays, swap both the relays to the other door (easy unplug and plug in) and try that. if it works on the other door then its the relay, you could also swap them within the door as one is up and one is down.
they are cheap and easy to get at NAPA-Bosch 12065116
 

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Just as important as providing 12 volts is providing the return path for the electric, the "ground". Hook the motor up and verify you have 12 volts at the motor. Up or down, it doesn't matter. Now check the voltage on the other wire, the ground. It should NOT read 12 volts. If it does then you do NOT have a good ground. Follow it and keep checking and where you find a spot that does not show 12 volts on the ground wire you are close to the problem. This is a "plastic" (fiberglass) car and everything must be provided a ground, you can't ground anything by attaching it to the body. Loose, bad, missing grounds can cause all kinds of weird "backfeeds". That power tries to go to ground and will backfeed any other circuit it can find it's way into. Look at the braid between the door and the body. Is it there? is it frayed and broken?
David Teitelbaum
 

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Fixed!

I looked at the grounds - they looked in great condition, replaced the relays with cheapies from the local auto parts store - Wahlah! Window works perfect.

I need to study the wiring diagram and figure out how we can bypass the relays to eliminate them as the problem. This was a common and easy thing to do with the 84 on Porsche 911, there was a relay for the ECU and it would become intermittent with age. We would bypass to diagnose - that relay is much more expensive so more important to eliminate before just changing parts.
 
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