Happy New Years guys,
I cleaned R/L ground connections behind headlights, minor dirt found, same for both motor/light connections. Still no low beam lights or raising of headlights. I check all related fuses again all appear in tact. I then access headlamp motors module, I manually raise both lights,unplug both from module, begin to plug back in and both go down like clockwork with no noise from motors...
I try stalk again....nothing....
I'm guessing it's the stalk ?????

 

Hi,

Have you got high beams? If you get high but not low, could be the selector for high/low. Stalk is a good suspect.

I'll try to put together a diagnostic path based on the manuals, but do check to see if the headlights are altogether failed, or only low beam. Also, check parking lights, since they are on the same switch in the stalk. I've had good luck with an electrical contact cleaner I bought at the local NAPA store for these, but it leaves a residue (sort of whitens the plastic), so you'll also want to wipe the excess right off. I pulled GENTLY on the rotary part of the stalk and sprayed the gap, and the lights worked more consistently. Same thing for other little switches and so on...

Hopefully I can get a consolidated diagnostic chart put together for you. Still could be the BCM, which does control all the lighting. I'll get the connector pinouts for you.

Good luck!

 

Here's the diagnostic tree for the situation where only the low beams are failed:

1. a) Disconnect connector C209 (instrument panel harness to steering column harness, LH side of steering column attached to IP lower beam)
b) Connect a fused jumper between terminals W and L (with the locking tab on top, L is at the lower left of the connector with the tab, or lower right of the opposite side; W is the battery positive feed, so should illuminate a test light - it's bottom row, fourth from right on the connector with the tab) I'll try to depict this:
___
|
K J H G F _|_ E D C B A
L M N P R S T U V W X Y Z


A B C D E |___| F G H J K
Z Y X W V U T S R P N M L

Do the low beam headlamps illuminate? Yes, go to 3; No, go to 2


2. a) Remove one of the low beam headlamp fuses:
HDLOBML = MiniFuse #10
HDLOBMR = MiniFuse #8

b) Connect a multimeter from the fuse terminal B in the underhood electrical center to the harness side of connector C209 terminal L. You'll need a long jumper, and I don't have a picture of the socket for the fuse, so can't advise as to which is "B" it is the one from C209. You'll be probing for resistance, so you should be able to use the voltage setting of the DMM to sort this out - the pin that has voltage when measured against ground should be A (not the one you want). The pin in the socket that has no power should be terminal B. Measure resistance between C209 and fuse terminal B. It should be between 0-2 ohms.
Is it in range? Yes, go to 4. No, go to Headlamps Inop, one lamp (probably an open in the circuit - unlikely in your case, since both are out).


3. Replace the headlamp switch. If this doesn't correct the problem, start over.


4. Repair the open in circuit 12 (between C209 and underhood electrical center). This is the circuit you tested in 2 above.


If both low and high beams are out, start by checking the HDLP MaxiCircuit Breaker #54. If memory serves, this is in the electrical center under the passenger floor, and these MaxiBreakers are interesting to locate. Our local Chevy dealer said they didn't exist, and the NAPA store took about a week to order one in. You test the circuit for looking for infinite resistance between the harness side of C209 terminal 2 and ground. If resistance is not infinite, you have a short to ground in circuit 842, which you'll need to locate and correct. It is tripping the MaxiBreaker.

If this resistance is infinite, you'll want to test the MaxiBreaker itself. If it is open (infinite resistance), replace it and see if that corrects the problem. If that isn't the problem, do the steps above - it's probably the switch.


Hope that helps - I've tried to extract information from several pages of the shop manual, so hopefully it's still coherent.

Good Luck!

 

Thanks for the continued help bowtierocket, will try and inform.....