Can't figure this one out

[Itsallstock!]

Hey guys, need a little help. I'm frustrated and stumped.


Drive my a4 on a 2hr road trip up to higher elevations. Drive was great. No issues. Stopped at the grocery store for about 30min. When I start the car to head to the house, heater won't come on, fan goes from lo to hi by itself but does not blow out any air, tach has a wicked delay, nothing on the cluster works correctly, no wipers, no turn signals. No headlights. No tail lights. Brights will come on but will not stay on. Battery and connections are good. All fuses are good. It must be something easy, I'm just frustrated and can use some help or guidance. I just don't get it. Everything worked when I got to the store and 30 minutes later nothing works and I drive to the house in the dark, no lights, and flashing brights every so often. Any help would be awesome. Thanks in advance.

Oh yeah, none of the dash switches work(fog lights, rear defroster) but hazards do work.

[Davdraco1]

I had my cluster just die on me one time. I ordered another on but it was wrong and my original cluster came back in about 2 weeks. I still to this day don't know why it did that. I would start by checking fuses, connections. The cluster comes out in about 2 mins. Make sure it's all plugged in properly. You can check the wires under the steering column to make sure they are wet or frayed. It's tough to really find a place to start but I would do the basics first. Maybe hook it up to a scanner or VCDS to see if your getting any codes. Hope this helps. Good luck!

[Itsallstock!]

Thanks for the help. I think I figured it out. I'm thinking it is the load reduction relay. It is the only thing I can find that would cause all the issues I seem to be having.

[walky_talky20]

I think you are very close with the load reduction relay, however the Headlamps (low beam and constant high beams) are NOT driven by the load reduction relay (or any relay for that matter). They are driven by the ignition switch output. That very same ignition switch output is also what drives the load reduction relay. So failure of the ignition switch will explain all of your failure items. I would feel confident in that diagnosis, based on your symptoms.

*The "Flash To Pass" feature of the headlamps (momentary high beams) is driven differently, as you found. It is driven directly from battery power. The rest of the headlamp features are powered via the ignition switch. The lack of relay driven headlights, in my opinion, is what kills the ignition switches and the headlight switches on the B5's. Driving that much load constantly through both switches is just a lousy, cheap and potentially unsafe design. <end rant>

You were nearly there (good work!), just need to go one step further up the chain. Best of Luck!

[Itsallstock!]

I have read that the infliction switch could also be the culprit. I have been looking for both but can not find them at the local auto part stores. Does anyone have part numbers for these two parts?

Walky thanks for your help. Greatly appreciated.

[walky_talky20]

Even if you found one at a local auto parts store, I probably wouldn't want to use it. I'd probably go for the "OE Aftermarket" one here:

https://www.ecstuning.com/Audi-B5_A4...ches/Ignition/

[Itsallstock!]

Thanks again, walky. You are the man.