So, the lights on my 1998 Audi A4 Quattro 2.3 V6 went on strike.
It’s a strange problem. All the bulbs and fuses are ok. Connections are tight. Parking and taillights are ok.
But, when you flip up the short lever/stalk that turns on the lights, they don’t come on. Neither the low beams or the high beams.
HOWEVER, the flash-to-pass high beams work!
Any ideas what might be causing this???
Not sure if your Audi has conventional bulbs or HID headlights. Your problems could be in the light switch, or in a relay(s) that are part of the light circuit. Relays are used so low current is routed into the switch. HID’s are even more complicated.
There have been instances of heat from the headlights melting the headlight housing and sockets. This isn’t and Audi problem, it is just something to look at as you troubleshoot your problem.
Allowing a professional a half hour to gather information that you could present to us would help, or at least help me. One technique in electrical diagnosis if to find a point in the circuit where things are working correctly and then continue testing until you find a point where things stop working. Two indespensible aids in diagnosis are,one, a through understanding of how the circuit is designed to work and ,two. a schematic of the circuit (and the ability to read the schematic).
I like to see these posts at least contain the sentence, "I am looking at the schematic for the lighting circuit for my car and I find that all is well up until…
The layman may just ask,“have you checked the inputs and outputs of the headlight switch”?
I would first test the switch at the stalk.
Also take a close look at the fuse sockets in the fuse box.
Another possibility, since its an Audi, is the ignition switch.
When they go bad, they can cause the problems you are experiencing.
So, admitting to myself that I don’t have any of the following: “a through understanding of how the circuit is designed to work and ,two. a schematic of the circuit (and the ability to read the schematic),” as oldschool suggested, I chose option B. Namely, oldschool’s suggestion to “find a point in the circuit where things are working correctly and then continue testing until you find a point where things stop working.”
circuitsmith suggested I start at the steering wheel end, so I did. I “removed” the steering column cover (I use the term “remove” quite loosely. My 2y/o would have done the job the same way were he strong enough. But epoxy should fix it right up…)
After some fiddling I managed to remove a large-ish (2", or so) modular plug right behind the dual turn signal and light stalks.
Improvising with a paper clip I started to make double, then triple, connections amongst the various holes. And lo, the lights came on!
So, I have a bad light-turning-on switch.
Even though I know of a great Audi junkyard that sells any and all manner of used Audi parts, and can likely easily procure both the switch and steering column cowling…I would not dare this switch repair myself.
Hence, my question now becomes…
How complicated is this repair?
That is, should I buy the used part, and take it to my intrepid local mechanic? At significant cost-savings.
Or, should I take the part to the dealer, and try to convince them to get one of the Audi-certified guys to fix it? At likely no cost-savings at all.
A decent independent mechanic can handle this.
The dealer will want to sell you a whole new steering wheel, or better yet a whole new car!
I must commend you as this is the most in depth any of the people I can remember over the past two years has gotten into their cars electrical system. Many people would be detured by the presence of the air bag but you got right in there, good job. I conclude you are asking both where to source a new part and how to complete the job? I will see what I can find online as I have only a generic idea as to the degree of difficulty you are going to face. I will say one thing though, if you start reassembly before I (or anyone else) gets back to you make absolutely sure that the turn signal lever in in the neutral (or off) position, there is a chance the canceling system breaks the stalk return tab off if the steering wheel is put back on with the lever in any position but in the middle. It has happened a few times before on BMW and those Germans like to share ideas.
EDIT:This is the headlight switch or the turn signal switch (with the HI/LO function on the stalk?)I see no diagrams at all for the 98 A4 but the 98A6 shows a headlight switch in the dash (but you say you removed the steering wheel, OK I see just the column cover, that is why no air bag trouble,still good job)Even for the A6 where headlight switch replacement is shown EBSCO does not show one detail about turn signal switch replacement. EBSCO’s fails here.No details about 98 A4 turn signal switch replacement, you are just going to have to “break trail” here.
Well, I ordered the part. We’ll see what my local guy will do!