jwbeck17

I know this is tough to digest, friends, as these are dark days indeed for my '89 S4. Timing belt issue? Too easy. Fuel line leak? That's child's play. It's far, far worse.

When I lock the driver's side door, the lock button does not flash anymore.

I know it's hard to digest, but it's true.

Ok, in all seriousness, I'm not sure what the deal is, so i unscrewed the button and swapped it with the working passenger side door button that lights up. Still the driver's side does not light up and the passenger side does, so it is not the button itself.

Any suggestions on what to check next?

BTW, great to see many of you at Frenzy!

Bertrand Daoust

There is a electric circular plastic part inside the door right under the button.

This is what's bad.

Change it and you should be good.

Had the same problem few years ago.

Let me check for the part #.

Bertrand Daoust

Pulse Sender.
928 637 137 00

jwbeck17

Thanks, Betrand!

Is the best way to get to it through the door card or through the top?

Bertrand Daoust

Don't remember well, but I think I had to remove the door panel (top section).

It wasn't a bad job.

linderpat

interesting Jason, I saw the flashing door lock button for the first time in the parking lot at Frenzy, very late Friday night. I just assumed it was the Frenzy "atmosphere" working it's magic on me. I never knew that the later cars had such a feature.

cool cars, still learning things. BTW, doesn't that function wreak havoc on the battery over time?

The Forgotten On

They're very low power leds. The pull a few milliwatts. I doubt they would cause issue as I have let my 89, that has them, sit for over a month and it started no problem.

StratfordShark

Now this caught my attention, as about the only system not working on my MY91 is the flashing LED door pins!

I know that they were working once, or at least the driver's side was.

I got hold of a new 'pulse sender' unit on ebay, and with it I verified that the driver side and passenger side pins both worked when I energised the flasher/driver.

It's kind of been at bottom of project list, but I had an idea that it could be the alarm module and was going to try a replacement for that module. Now you've got me thinking that maybe that pulse unit has failed on both sides, and that I hadn't noticed the passenger side fail before the driver side.

Since I have a new unit, I may try replacing the driver side and seeing if that does the trick. If so I'll be looking on ebay for another flasher unit, but the one I bought is the only one I ever saw for sale!

dr bob

The "alarm-primed indicator lamp" receives primary power through the same circuit that supplies the door courtesy lights via fuse 25 in MY 1991 cars. These are red conductors to each LED module. The alarm module selectively grounds each of the the LED modules separately: Green/blk from the driver's side module to alarm module terminal 15, green/yellow from the passenger's side to alarm module terminal 14. Note that the power to the LED modules passes to (but not through) the connector to the adjacent light on the door lock in each door.

jwbeck17

Since the driver's side doesn't light up but the passenger side does, I suspect the first culprit to check would be the pulse sender that Bertrand mentioned, correct?

To check the pulse sender, do I need to remove the entire door panel, or is there an easier way?

This was what I saw online:

http://jenniskens.livedsl.nl/Technic...el_removal.pdf

Just trying to determine if i need to get a new one from Roger, or is there another culprit.

dr bob

Remove the door panel. The LED module sits under a clip under the top of the door panel, just forward of the lock button itself. WSM offers no detail on what's inside the module, and no guidance on whether the current limiting and/or the "flash" function happens there or in the alarm module.

StratfordShark

The flash function does happen in the LED module. Just has two wires coming from it for 12V supply, and when that's applied current is pulsed through the coil the door pin sits in. You can play with it using a little 9V battery and one of the door pins!

Bertrand Daoust

You can also check continuity on the pulse sender to confirm it's bad.

jwbeck17

Well i just replaced the pulse sender, but no luck. the lock light won't go on. I then tested the original pulse sender and tested for continuity by connecting my multimeter to the two prongs of the pulse sender connector, and no continuity there, so at least I believe I replaced a bad part.

The passenger side is still working correctly.

Based on Dr. Bob's explanation, I suspect it could be the drivers side connection to the the alarm module Terminal 15. possibly?

Any other suggestions of where to check?

Bertrand Daoust

It's been a while since I replaced mine, but if I remember well, the new one wasn't working either... Until I flipped the connections.
I had to force it as it is a one way connector but it was only working that way.
Flipped connections in the new part I guess.

Worth a try maybe...

Good luck.