forrest forrest gump

My lights wont go up or down.

I have factory service manuals and tested accordingly. It said replace headlamp actuator module. I got one from a salvage yard, didnt fix the problem. Get another, then another, thinking maybe the boneyard actuators were also bad. I get someone to plug in one to their car, and it works. (now i have 4 seemingly good actuators if someone is in need).

My motors are good. I can run them up and down w/ 12 volts. Nice and smooth.

I originally ruled out the light switch because the proper signals were making it to the actuator connectors. 12V on the "on circuit" with switch on and 12V to the "off circuit" with switch off.

I tried to run the actuator without the switch by puting 12V on the proper circuits, but did not work. I wasnt able to get the actuator to run the motors up and down.

I cleaned ground packs on each frame rail.

Now I am running out of ideas and patience. I am starting to suspect the light switch again...

Anybody with similar type problems. This thing is killing me.

JC in XTC5

Sounds like you've tried just about everything to test the individual segments of the circuit.

Maybe this will help get some more ideas going.

You said you tested the motors directly. I assume you disconnect the wiring harness just behind the headlight and apply +12V and -12V on the two motor pins and it works fine. That should prove the motor is fine. However from what I've read and tested it appears that the motor current is what triggers the headlight control module to open it's connection (i.e. stop applying power to the headlight motor). The current will rise when the motor arm hits a stop causing the control module to open the circuit. I don't know what the current threshold is and I wouldn't expect both headlights to experience some type of problem, like a binding motor arm, at the same time but it's worth checking.

If the switch was the problem then both the headlight bulbs and the motors would be OFF or not working at the same time since the same contact on the switch is used for both circuits. When you turn the switch ON do the headlights come on even though they don't raise? If they do then it's not the switch.

It still seems to point to the area of the control module as the source of the problem since even when you apply +12V to the on circuit it doesn't work. So the next step is test all the connectors to/from the control module and to/from the headlight motor. The connectors in these cars are notorious for a broken wire or poor contact. Since both lights are not working this points to the control module input connector. Unplug the connector and test the continuity of the ground pin in the connector to a ground point. Also do the same for the On signal pin so you see +12V when the switch is ON. I would bet the problem is in the connector itself.

Let us know if this helps.

forrest forrest gump

Thanks for the reply.

First. Yes the headlight do light up, even though they dont go up and down. So your reasoning is that it is not the switch. (I don't disagree, just baffled at this point)

Second. This is how I ruled out the connector inputs to the actuator. While at the salvage, I cut the connectors off the donor car. This is how I tried to drive the system manually using 12V. I was unable to drive it with my inputs. I put constant 12V to the orange wires (B & E). I put a constant ground to the black wire (D). I then applied +12V to yellow wire (A) which is the open circuit. This did nothing. I did the same with the brown wire (C) which is the close circuit. Again nothing happened. I did this with multiple different actuator (Remember I have 4 now.).

Third.
I also took a headlamp motor from the salvage yard. I performed all the same test with the system, using the junkyard motor. Again I could not get it to move using the actuators, but could drive it by applying +/-12V.

I tried to isolate and eliminate each part of the entire circuit, but could never eliminate anything. Still the sum of the parts dont work.

JC in XTC5

That's interesting. So even with a test motor would not work through the test actuator.

Tonight I'll go through the schematics and see if I can suggest more ideas.

forrest forrest gump

I appreciate any assistance.

JC in XTC5

Just looking through the schematics and you're checking the same things I would in connector C1. The only comment is you're referring to Pin A as yellow and Pin C as brown - my manual says white (A) and Dark Green (C) but I'm just putting that in as an observation. I don't think it's relevant but it should be noted. What year is your car? Could there be a difference in the control module for different model years? That might explain some of the problems.

One thing I remembered when I was troubleshooting my headlight issue. When the lights are OFF, both wires to the motors are at +12V for a net 0V across them. When the light switch is turned ON, the control module grounds one of the motor wires resulting in a net +12V across them. What is the voltage of these wires in normal OFF state? Driver's side connector behind the headlight is A - Dark Green and B - Light Green, and passenger side is A - Dark Blue and B - Light Blue. The control module is suppose to ground the Dark wire to Open the headlight, then ground the Light wire to Close the headlight.

So, if you take one of your new control modules and repeat your test: put +12V on C1 pins B & E (Orange) and Ground Pin D (Black), and leave Pins A and C Open, what is the Voltage on Pins C2 pins A, B, C, and D. They should all be +12V.

If you then apply +12 to C1 Pin A (Open), then C2 Pins B and C should go to ground for a few seconds, but I believe the control module will not keep them there indefinitely and eventually switch them back to +12V.

If you can't see these voltages on the corresponding pins then there has to be a problem in these control modules.

forrest forrest gump

Thank you JC.

I pondered more based on your post.

I could not get my modules (any of the 4 I have on the shelf) to trigger a neg 12V on the opposite leg of the motors, even when I applied voltage to the A (on) or C (off) circuits.

Soooooo. I bought another one. I couldnt bring myself to pay stealership prices, so I posted on the C5 ads that I needed one.

A nice guy sent me one shipped for $45.

Got it today. Plugged it in, and my lights worked.

They went up and down just like they should.

Thanks for backing me up on this one. I appreciate the help.

JC in XTC5

Great News!