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If HID lights were added they can cause the problem of the motors not closing unless the high beams are selected, this is due to the reduced current draw of the more efficient HIDs. Most owners add power resistors to increase the current draw so the lights will open and close as they did with the old lamps. Did you remove the control module and check it for defects as seen in the above photos such as a warped cover that can let in water?
People have made some suggestions regarding things you can check in this thread, and in the one you started. You just need to get in there and do it. It's not going to fix itself.
I located a used on from a used Vette parts online store for (This works for me) $99.00 and free shipping. Now, I will remove the clicking unit and open it and check for moisture inside the unit. May as well silicone the seems of the replacement unit once it arrives.
I will post some photos once I open the currently installed defective unit.
It seems that most everyone buys these things used. I got the shock of my life when the dealer told me these modules cost $675.00 new.
The guy at the parts desk recommend finding a used one at the bone yard or Ebay. My unit is ticking. It is not getting warm. It's only making a ticking sound.
I just ordered a reconditioned headlight control module for $125 from:
This was after my mechanic had touched the solder joints of my board with a hot iron without luck.
Someone else report that tapping his board caused the lights to move suggesting a bad relay on the board and replaced the relay (soldering required) in 2009 with one from:
The relay is made by Omron, and the part # is MY4-02-US 12VDC.
I have only found it at one source: California Radios Plus, $13 plus $7 shipping.
There is a replacement part made by Omron that is sold by many,
including Mouser Electronics, and it is cheaper than the original
part. The problem is that it has flat terminals on it, and the original
has pins that are soldered to the circuit board. I assume that if you
were a patient sort, you could modify the relay and/or the board to
accept the replacement, which is only $6 plus shipping.
The FIRST thing that I recommend doing is checking the little plastic pads that the headlight module stops against when its UP & DOWN. They get smashed/missing and can cause weird issues with the module when the headlight module is stopped.
Sounds like its on the very edge of its TORQUE limit of being seated.
Hey guys, I know that's an old post, but I was wondering if one of you guys had a better picture of the circuit. I was hoping to modify that module to work with LED bulbs so the lights go up and down without needing an external resistor.
I have been dealing with my module in a 1998 corvette to try and fix it and would like to share some info I got. It may help you to replace components, test resistors, diodes and capacitors and to eventually make a new board (layout and gerber file included - I used Sprint Layout 5 to copy the tracks of the board). I couldn't find a place to buy the replacement for the "board inserts" (male plug), for the Omron relay (even though MY4 are easy to find, but not 9V) and the proprietary GM controller (made by ON Semiconductors). Eventually I am going to prepare the case for 3D printing and share the file.
Controller:
IC1 - 16512455 UEN00403 ON -
pins:
1 - gnd
2 - VSS? linked through R10 to (+) and to pin 6 via R9. Have C2 to estabilize.
3 - n/c
4 - controls the opening of Q3 via (-) - relay power
5 - linked to pin6 via R8
6 - linked to pin 2 via R9. Have C2 to estabilize.
7 - input from headlights ON state
8 - gnd
--
9 - input from headlights OFF state
10 - gnd
11 - input from drain of Q2 - senses if Q2 was opened. Goes through R6
12 - connected to (+) through R3
13 - connected to (+) through R5
14 - input from drain of Q1 - senses if Q1 was opened. Goes through R4
15 - controls gate/opening of Q2 - energy (-) to F2 that feeds the relay. Goes through R14
16 - controls gate/opening of Q1 - energy (-) to F2 that feeds the relay. Goes through R15
Connector pins:
(9x) 2.8mm (1/8") insert pcb / 30mm height / 0.9mm thickness
(to be replaced by wires leading into a male connector)
Black plastic Base for connector:
1x base - 12mm height 9mm width 29mm large (4pins)
1x base - 12mm height 9mm width 37mm large (5pins)
in my device i have the (Q3 - f D345 7621) looks damaged but i can not find it in any market. even no any result on google search for (f D345 7621). so can you advice me what equivalent i could use instead of it.
WOW! What a POS part. That "circuit board" looks like something out of my late 70's High School electronics (you know, HIFI, 8 Track, reel-to-reel, CB radios) class. Nice job moving to the new millenium GM!
It appears to be a designed PC board from back of the day when "sparkys" were developing PC design . Give them "sparkys designers"a break Bunkey! Where were you in 1989.. with your skate board?
I'm having issue with mine now, I was quoted $1500 with labor to replace the module, left side headlight motor, & headlight wiring harness. I'm looking for less expensive options.
09-30-2016, 02:18 PM
