Hi all - I live in California and am helping my son who is in Colorado to diagnose his lighting issue. As I do not have the car nearby and only worked on the car once, while replacing the infamous head gaskets, I am admittedly a little under informed. But here goes - and appreciative in advance for any help:
Situation: Both low beams and Daytime running lights(which he tells me are the side marker lights??) are not operating. Hi beams work. Bulbs passed continuity check, Relay has been swapped and indicates normal operation. He disconnected the DLR and this did not allow the low beams to operate.
I have done some research and it suggests the following - but I am not sure. Here are my conclusions - point x point. Please correct me if wrong:
1. Body control unit - has no relation to headlight operation.
2. Illumination unit - has no relation to headlight operation
3. DLR - would have thought this was the culprit but when disconnected it did not resolve the problem. ( I should note that he to thought the bulbs were the problem and replaced them with LED bulbs - I point this out just in case this clouds the result of the DLR relay disconnection test.
4. Connector near firewall - I read somewhere that someone had a problem with this; cleaned it and it fixed the problem. He has not located this yet.
Any thoughts on the conclusions made and what steps he can take to diagnose the issue. Many thanks - Harvey
