Headlamp motor

DanielForest

DanielForest

True Classic
Hi,

To make a long story short, my car is in a heated garage in storage for more than18 years. The headlamp were working 18 years ago but it is no surprise some components could be failing after such a long break.

The left hand (driver side) motor on my 1980 X1/9 isn't retracting. The lights are working, the headlamps are rising, but the left one didn't want to go down. I checked the fuses and relays. I swapped them. Nothing change. So my guess was one diode was bad. I replaced the diode. No change. So my next step was to do some testing with other headlamps motors. I have some spares, most for the 1300cc engines, so I started with the later 1500cc ones. Easy to differentiate because of the different plugs.

I tried all the 1500cc headlamp motors (even the right hand ones) and even if some of them would raise, none would go down. But the right headlamp is always closing, so it's not the fuse.

Then I tried the 1300cc headlamp motors, plugged with some alligator clips wires. Exact same results. After 7 headlamp motors, none of the were rectracting, and only a few were rising.

So my assumptions are:
it's not the fuses or the relays. If I moved them (fuses and/or relays) to another location, there are no changes. And the right headlamp is always rising up and down.

If it's the left headlamp the problem I have been really unlucky with 7 bad motor diodes. Even if I didn't do a good job of welding the diode on the first headlamp motor, there would be no reason for all the 6 other ones to not work.

That leaves only the wiring... but it was working 18 years ago and the car is sleeping since then. Maybe some mices? I probably should do some continuity testing on the wires, unless somebody point out something I forgot...
 
Each motor has 5 connections, 2 for the actual motor, and three for position sensing. Of those three, one is common, one is the "up" wire and one is the "down" wire. The "up" wire should have continuity to the common wire for most of the travel, except when the headlight is in the up position. Similarly, the "down" wire should have continuity to the common wire for most of the travel, except when the headlight is in the down position. You can easily test this with a multimeter while turning the motor by hand. Disconnect power from the motor before doing the test. I don't have the wire colors handy, but I assume you have a wiring diagram.

My guess is that the "down" switch / wiper in the motor does not make a connection when it is supposed to.
 
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If I remember correctly, a bad diode on the other headlight (that operates properly itself) could do this?
 
See the electrical section in the wiki. Tons of great info on headlights. I totally rewired mine from it

Odie
 
Jefco said:
If I remember correctly, a bad diode on the other headlight (that operates properly itself) could do this?
Click to expand...
Yes, a shorted diode in one headlight will cause the other headlight not to stop when it is supposed to. An open / no-connect will affect only the headlight where the open / no-connect is.
 
ng_randolph said:
Each motor has 5 connections, 2 for the actual motor, and three for position sensing. Of those three, one is common, one is the "up" wire and one is the "down" wire. The "up" wire should have continuity to the common wire for most of the travel, except when the headlight is in the up position. Similarly, the "down" wire should have continuity to the common wire for most of the travel, except when the headlight is in the down position. You can easily test this with a multimeter while turning the motor by hand. Disconnect power from the motor before doing the test. I don't have the wire colors handy, but I assume you have a wiring diagram.
My guess is that the "down" switch / wiper in the motor does not make a connection when it is supposed to.
Click to expand...

You lost me after "Each motor has 5 connections...". Anything with more than "power" and "ground" and I'm confused...

Jefco said:
If I remember correctly, a bad diode on the other headlight (that operates properly itself) could do this?
Click to expand...

That is opening some new possibilities...

autox19 said:
See the electrical section in the wiki. Tons of great info on headlights. I totally rewired mine from it
Odie
Click to expand...

Wiki? Is that an Australian terrestrial mammal?

Thank you for all your tips, including Jeff encouragment. I will keep searching, but don't expect news soon. I don't have much time, so I probably did my 2 hours of the month today.
 
The bad diode on the other headlight (shorted, works just like straight wire) cancels the down signal from the switch... and the other one stays up.
You could try unplugging the 'good' light to take it out of the equation.
 
I found the wire colors in the 1980 Electrical Troubleshooting Guide. Each motor should have 5 wires coming out:

  1. A lonely black wire that is the ground connection for the motor.
  2. A solid green wire ending up in a 2-pin connector. This is the +12V connection for the motor.
  3. A green wire with a black stripe. This is the "down" signal, and the wire ends up in the same 2-pin connector as #2 above.
  4. A Grey wire that ends up in another 2-pin connector. This is the "up" signal.
  5. A black wire that ends op in the same 2-pin connector as #4 above. This is the common signal.
Turn the knob on the back of the motor to set the headlight somewhere between fully closed and fully open. Get out your multimeter (and if you don't have one, best $10 you'll ever spend) and set it to diode test (if available, or continuity test otherwise). Put the red probe to the GRN/BLK (#3 above) and the black probe to BLK (#5 above). On diode test you should see something around 0.7V, and on continuity test you should see continuity. Now switch the red and black probes. You should see no continuity, and diode test should read infinite.

Then put the red probe to GRY (#4 above) and the black probe to BLK (#5 above). Again, on diode test you should see something around 0.7V, and on continuity test you should see continuity. Now switch the red and black probes. You should see no continuity, and diode test should read infinite.
 
Daniel Forest said:
Thanks guys. Great info. I will let you know the results.
Click to expand...
It's the switch.

I have a 79 that sits for long periods of time. The switch has grease in it that dries out and prevents a contact from making on the down circuit. Work the switch 20 times back and forth rapidly and see if it will now retract. You should take the switch apart and clean it, but be careful as there are a lot of little bits in there that can get lost in a hurry.

TonyK.

Grimsby Ontario Canada.
 
TonyK said:
It's the switch.

I have a 79 that sits for long periods of time. The switch has grease in it that dries out and prevents a contact from making on the down circuit. Work the switch 20 times back and forth rapidly and see if it will now retract. You should take the switch apart and clean it, but be careful as there are a lot of little bits in there that can get lost in a hurry.
Click to expand...

I just changed it... but it is still an old used switch. Another thing to check.
 
ng_randolph said:
Turn the knob on the back of the motor to set the headlight somewhere between fully closed and fully open. Get out your multimeter
Click to expand...
Bjorn, excellent info - thanks.


TonyK said:
The switch has grease in it that dries out and prevents a contact from making on the down circuit.
Click to expand...
But if I understood correctly, the "down circuit" is working...the other headlight goes down as it should.
 
But it is so much warmer and comfortable in front of the computer. And carpal tunnel is your biggest health risk, compared to all the carcinogens you are exposed to in the garage - not to mention lacerations, bruises, abrasions, and headaches. And if you get tired of automotive content, just switch back to that porn page you have bookmarked Daniel. :oops:
 
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ng_randolph said:
I found the wire colors in the 1980 Electrical Troubleshooting Guide. Each motor should have 5 wires coming out:

  1. A lonely black wire that is the ground connection for the motor.
  2. A solid green wire ending up in a 2-pin connector. This is the +12V connection for the motor.
  3. A green wire with a black stripe. This is the "down" signal, and the wire ends up in the same 2-pin connector as #2 above.
  4. A Grey wire that ends up in another 2-pin connector. This is the "up" signal.
  5. A black wire that ends op in the same 2-pin connector as #4 above. This is the common signal.
Turn the knob on the back of the motor to set the headlight somewhere between fully closed and fully open. Get out your multimeter (and if you don't have one, best $10 you'll ever spend) and set it to diode test (if available, or continuity test otherwise). Put the red probe to the GRN/BLK (#3 above) and the black probe to BLK (#5 above). On diode test you should see something around 0.7V, and on continuity test you should see continuity. Now switch the red and black probes. You should see no continuity, and diode test should read infinite.

Then put the red probe to GRY (#4 above) and the black probe to BLK (#5 above). Again, on diode test you should see something around 0.7V, and on continuity test you should see continuity. Now switch the red and black probes. You should see no continuity, and diode test should read infinite.
Click to expand...

It was looking so simple.. but...

Agree on the wires colours. Found the diode test on the multimeter.

Turning the knob between fullyy closed and fully open is not working for me. The headlamp door is disconnected, so I don't have any clue where I am.

In testing I got some conductivity on the green... but I got the same results reversing the black and red probes. On the other hand, I don't get any conductivity with any other wires...

I tested 2 motors with the same results...

Thats doesn't fit with your tips...
 
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Did you try just unplugging the 'good' one and trying the 'bad' light by itself?
(To eliminate interaction).
 
First time in a month I have time to go in the garage and it's not freezing to death. Did some more testing by unplugging the working side, as suggested. My difficulty is all the plugs are removed so I have to guess which wire goes where... But I found a position where the motor is working...endlessly. But only for raising. BTW, the motor is removed from it's position, so there is no "stoppers". So I guess the endless motion is right, but that would mean the closing diodes is not working OR the wiring for the down position is reverse...

I'm thinking about starting a new thread and call it "I hate electricity more than I can express". I would do bodywork all day long, but anything with more than 2 wires is puzzling me.
 
How were the headlight motor relays tested? How were the wire connections to the headlight motors tested?

The headlight motors can be tested by applying 12-15 volts DC power to the motor to verify and confirm the motor runs. Connect the negative or often black wire to the body of the motor, this is ground. Connect the positive 12-15 volts DC power to the single wire (likely green wire) that goes directly into the motor's body. The motor should run upon application of power. If the motor does not run and connections-power are verified good, the motor is NG.

Test to see if the motor switch and diodes is good. There are three wires that goes to the switch on the gear inside the headlight motor. The center connection goes to the motor positive power (likely green wire). Apply a jumper clip between this connection of the switch to the motor power wire. Connect the negative or often black wire to the body of the motor, this is ground. Apply 12-15 volts DC power to each of the wires with the diodes connected to them, alternate this connection if the motor does not run. These connections alternate between switch connections inside the motor's gear.

The motor only runs in one direction.

If the motor, diodes and switch are good, it will pass these test and problem of the head light not going up_down is in the headlight switch, headlight motor relays or wiring. The headlight motors can be interchanged or run individually to check for operation. They do not need to be mechanically installed to test for operation.

BTW, this headlight motor system design is used on the Mazda MX-5 aka Miata. Mazda swiped this intellectual property from Berton-Fiat then used it on the MX-5_Miata. Only difference is the motors in the MX-5 are a more modern design, but function and innate design is identical.


Bernice
 
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