Electronics Need help wiring something up? Thinking of adding an electrical component to your car? Need help troubleshooting that wiring glitch?

Headlights go up but do not go down

Thread Tools
 
Search this Thread
 
Old 03-09-2012, 11:23 AM
  #1  
Member

Thread Starter
iTrader: (1)
 
LostX's Avatar
 
Join Date: Mar 2011
Location: Starkville
Posts: 221
Likes: 0
Received 0 Likes on 0 Posts
Car: 88 Trans Am
Engine: 350
Transmission: T5
Axle/Gears: Posi
Headlights go up but do not go down

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
Old 03-09-2012, 11:24 AM
  #2  
Member

Thread Starter
iTrader: (1)
 
LostX's Avatar
 
Join Date: Mar 2011
Location: Starkville
Posts: 221
Likes: 0
Received 0 Likes on 0 Posts
Car: 88 Trans Am
Engine: 350
Transmission: T5
Axle/Gears: Posi
Re: Headlights go up but do not go down

What else should I test with the volt meter
Old 03-14-2012, 12:53 PM
  #3  
Moderator

iTrader: (2)
 
lonsal's Avatar
 
Join Date: Dec 1999
Location: Hacienda Heights, CA
Posts: 5,954
Received 29 Likes on 23 Posts
Car: 90 RS 'Vert, 88 IROC-Z, 88 Firebird
Engine: 305 ci tbi, 305 ci tpi, 350 ci tpi
Transmission: WC-T5, WC-T5, 700R4
Axle/Gears: 3.45, 3.27, 3.27
Re: Headlights go up but do not go down

Relace the tail light fuse.

Lon
Old 03-14-2012, 05:50 PM
  #4  
Member

Thread Starter
iTrader: (1)
 
LostX's Avatar
 
Join Date: Mar 2011
Location: Starkville
Posts: 221
Likes: 0
Received 0 Likes on 0 Posts
Car: 88 Trans Am
Engine: 350
Transmission: T5
Axle/Gears: Posi
Re: Headlights go up but do not go down

Originally Posted by lonsal
Relace the tail light fuse.

Lon
the taillight fuse is good. just checked it
Old 03-30-2012, 12:28 AM
  #5  
Member
 
lethaldomestics's Avatar
 
Join Date: Apr 2011
Posts: 315
Likes: 0
Received 2 Likes on 2 Posts
Re: Headlights go up but do not go down

anymore on this i am having the same problem.
Old 03-30-2012, 07:30 AM
  #6  
Moderator

iTrader: (2)
 
lonsal's Avatar
 
Join Date: Dec 1999
Location: Hacienda Heights, CA
Posts: 5,954
Received 29 Likes on 23 Posts
Car: 90 RS 'Vert, 88 IROC-Z, 88 Firebird
Engine: 305 ci tbi, 305 ci tpi, 350 ci tpi
Transmission: WC-T5, WC-T5, 700R4
Axle/Gears: 3.45, 3.27, 3.27
Re: Headlights go up but do not go down

Originally Posted by LostX
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 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
Old 03-30-2012, 09:27 AM
  #7  
Member

Thread Starter
iTrader: (1)
 
LostX's Avatar
 
Join Date: Mar 2011
Location: Starkville
Posts: 221
Likes: 0
Received 0 Likes on 0 Posts
Car: 88 Trans Am
Engine: 350
Transmission: T5
Axle/Gears: Posi
Re: Headlights go up but do not go down

the control module is from a 1990 but it looked identical to the one from my 88.
Old 03-30-2012, 09:49 AM
  #8  
Junior Member

 
nathan44's Avatar
 
Join Date: Sep 2007
Location: dallas, tx
Posts: 36
Likes: 0
Received 0 Likes on 0 Posts
Car: trans am
Engine: 5.3 l59 flex
Transmission: 4l60e
Re: Headlights go up but do not go down

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.
Old 03-30-2012, 12:22 PM
  #9  
Moderator

iTrader: (2)
 
lonsal's Avatar
 
Join Date: Dec 1999
Location: Hacienda Heights, CA
Posts: 5,954
Received 29 Likes on 23 Posts
Car: 90 RS 'Vert, 88 IROC-Z, 88 Firebird
Engine: 305 ci tbi, 305 ci tpi, 350 ci tpi
Transmission: WC-T5, WC-T5, 700R4
Axle/Gears: 3.45, 3.27, 3.27
Re: Headlights go up but do not go down

Originally Posted by LostX
the control module is from a 1990 but it looked identical to the one from my 88.
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
Old 03-30-2012, 01:44 PM
  #10  
Member
 
lethaldomestics's Avatar
 
Join Date: Apr 2011
Posts: 315
Likes: 0
Received 2 Likes on 2 Posts
Re: Headlights go up but do not go down

question: where are the inline fuses?
Old 03-30-2012, 02:18 PM
  #11  
Moderator

iTrader: (2)
 
lonsal's Avatar
 
Join Date: Dec 1999
Location: Hacienda Heights, CA
Posts: 5,954
Received 29 Likes on 23 Posts
Car: 90 RS 'Vert, 88 IROC-Z, 88 Firebird
Engine: 305 ci tbi, 305 ci tpi, 350 ci tpi
Transmission: WC-T5, WC-T5, 700R4
Axle/Gears: 3.45, 3.27, 3.27
Re: Headlights go up but do not go down

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
Old 03-30-2012, 02:27 PM
  #12  
Moderator

iTrader: (2)
 
lonsal's Avatar
 
Join Date: Dec 1999
Location: Hacienda Heights, CA
Posts: 5,954
Received 29 Likes on 23 Posts
Car: 90 RS 'Vert, 88 IROC-Z, 88 Firebird
Engine: 305 ci tbi, 305 ci tpi, 350 ci tpi
Transmission: WC-T5, WC-T5, 700R4
Axle/Gears: 3.45, 3.27, 3.27
Re: Headlights go up but do not go down

Originally Posted by nathan44
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.
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
Old 03-30-2012, 03:07 PM
  #13  
Member

Thread Starter
iTrader: (1)
 
LostX's Avatar
 
Join Date: Mar 2011
Location: Starkville
Posts: 221
Likes: 0
Received 0 Likes on 0 Posts
Car: 88 Trans Am
Engine: 350
Transmission: T5
Axle/Gears: Posi
Re: Headlights go up but do not go down

Originally Posted by lonsal
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
im going to test my old control module this weekend and if it doesnt work ill message you to buy one. thanks
Old 04-01-2012, 07:32 PM
  #14  
Member
 
lethaldomestics's Avatar
 
Join Date: Apr 2011
Posts: 315
Likes: 0
Received 2 Likes on 2 Posts
Re: Headlights go up but do not go down

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.
Old 04-04-2012, 01:14 AM
  #15  
Moderator

iTrader: (2)
 
lonsal's Avatar
 
Join Date: Dec 1999
Location: Hacienda Heights, CA
Posts: 5,954
Received 29 Likes on 23 Posts
Car: 90 RS 'Vert, 88 IROC-Z, 88 Firebird
Engine: 305 ci tbi, 305 ci tpi, 350 ci tpi
Transmission: WC-T5, WC-T5, 700R4
Axle/Gears: 3.45, 3.27, 3.27
Re: Headlights go up but do not go down

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

Lon
Old 04-04-2012, 07:10 PM
  #16  
Member

Thread Starter
iTrader: (1)
 
LostX's Avatar
 
Join Date: Mar 2011
Location: Starkville
Posts: 221
Likes: 0
Received 0 Likes on 0 Posts
Car: 88 Trans Am
Engine: 350
Transmission: T5
Axle/Gears: Posi
Re: Headlights go up but do not go down

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
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
Cam-aro
Camaros Wanted
2
11-12-2015 03:35 PM
J. Chris Davis
Interior Parts Wanted
2
09-28-2015 11:55 AM



Quick Reply: Headlights go up but do not go down



All times are GMT -5. The time now is 07:39 AM.