I replaced both motors, the wiring loom containing 2 green and 2 gray wires, the control module, and the headlight switch from a working parts car. Both red wires are getting 12v and the yellow and white wires alternate 12v when the headlight swith is flipped on and off. When power is plugged in to the control module the motors go automatically up to a default position. I have to lower them manually and then I can use the headlight swith to bring the motors up once and only once. Then I have to reset the system by unplugging the power tv the control module.
The car is a 1988 firebird with the 2 wire motors

 

What else should I test with the volt meter

 

Relace the tail light fuse.

Lon

 

the taillight fuse is good. just checked it

 

anymore on this i am having the same problem.

 

What year was the "working parts car"? It should have been a 87-89 model year. If the parts car is a 90-92, then your headlight control module is wrong. You'll need a module from a 87-89. Test the module per the charts on page 8A-102-1 of your 1988 Firebird Service Manual (available online from HELMinc.com or eBay). Potential problems are: headlight control module, fuesable link(s), wiring, tail lamp fuse. It also can be mechanical binding in the actuator motor. The symptom of that would be that the **** on top of the motor is stuck ad hard to turn when you first try to turn it. Let me know if this is the problem I'll supply the solution.

Lon

 

the control module is from a 1990 but it looked identical to the one from my 88.

 

i had a similar issue, however if you research it there is a way to use an auxilarry fuse as the backup to raise and or lower headlights.

 

Yes it does look identical (even having the same number molded in the cover) but it's not the same internally. The circuits are different. You'll need the module from a 87-89. I have them available if you need one.

Lon

 

question: where are the inline fuses?

 

Inline Fuses:

Fuseable Link D front lights harness, near LH side of dash (.8 color BLUE, connects to a RED wire)
Fuseable Link E front lights harness, near LH side of dash (.8 color BLUE, connects to a RED wire)
Fuseable Link G front lights harness, near LH side of dash (.5 color RUST, connects to a red/white stripe wire)

Lon

 

And what would shut off the headlight motor? Unlike the 82-86 3-wire headlight actuator motor, there is no internal limit switch to shut it off. The Headlight control module turn on the headlight motor for either up or down, then senses the spike in current when the headlight bucket reaches it's physical stop and shuts off the motor. However, when the bushings inside the gear have broken down into chunks, there won't be a spike in current when the headlight bucket reaches it's stop. The gear will continue to turn and the motor continues to run. Fortunately there is a secondary backup circuit inside the headlight control module that shuts off the motors after 6 seconds if the module has not sensed that spike in current. I do not recommend Jerry-Rigging the switching on/off of the motors. Repair them properly is my recommendation.

Lon

 

im going to test my old control module this weekend and if it doesnt work ill message you to buy one. thanks

 

Ok so i had the prob with them going up and not down. as i had prevs. stated. it was the headlight switch. they work perfect now. i also snagged a couple of modules from the local rec yard for back up.

 

OK, Top-Down Solutions new and improved web site is FINALLY up and running. Thanks everyone for your patience.

Lon

 

i fixed it. i had a 1990 control module and a swapped back to my 88 module. My old one was still broken since only the left light worked but it went up and down. I just opened the module up and soldered an internal fuse that blew labeled F1 and it works. thanks