Backlit Electronic Instrument Cluster

[dmc6960]

UNFORTUNATELY it seems handling a fuel level sender like a shake-weight is counterproductive to its lifespan. It is now broken. To make matters worse, this generic VDO-built unit for 1983-1987 Saab 900's*** is no longer available. I THINK I have one ordered from a parts house that still has one in stock, but we'll see.

Well, unfortunately it seems the place I found which said they were "In Stock" does not actually have them "In Stock". I've received a message stating...

Upon processing your order, our manufacturing facility has informed us that the following item(s) are backordered with a new Estimated Ship Date as shown below:
New Estimated Ship Date: 4-6 weeks
Reason: Manufacturing Delay (Build to order part)

I responded that I would like to wait the 4-6 weeks. However if this truly no longer manufactured, I'm just out of luck on it I guess. I could buy a used one on eBay, but I have other things I can continue working on in the mean time. I don't need it to test the pointer acceleration logic, I can do that manually. Of which, I believe I'm between 1/3 and 1/2 of the way completed with that programming. After that works, I'll incorporate a second gauge into the logic, and get the test setup into the car.

After that I'll work on the tachometer.

[Bitsyncmaster]

That VOD sender has a very fine nichrome wire. You may just need to clean it. I used some scotch brite pad to very carefully polish the wire in mine.

[dmc6960]

You think it just needs cleaning? This was a brand new unit never installed into a car. It now reads open across the whole range of the float. The low level light still closes. It happened sometime after I shook it rapidly back an fourth. This was to observe the needle pointer response and see if it skipped any steps. It didn't fail while I was doing that though, and I lost several hours on the program after it stopped working and I thought I screwed something up.

[Tomcio]

.... This was to observe the needle pointer response and see if it skipped any steps. It didn't fail while I was doing that though, and I lost several hours on the program after it stopped working and I thought I screwed something up.

Jim,
Why don't you use a potentiometer instead of the actual sender? Use a straight type to better visualize the set level. You can move it as fast as you'd like and if it breaks you're out 50 cents. AFAIR the sender reads 0 at one end and 90-100 ohms at the other. It should read 0 at empty and if the resistance gets too high at full the pointer will actually show more that full - with the failed or disconnected sender (open) the needle points straight up. So it's easy to find the max resistance required.
I'm thinking about something like this:
Potentiometer.jpg

[Bitsyncmaster]

You think it just needs cleaning? This was a brand new unit never installed into a car. It now reads open across the whole range of the float. The low level light still closes. It happened sometime after I shook it rapidly back an fourth. This was to observe the needle pointer response and see if it skipped any steps. It didn't fail while I was doing that though, and I lost several hours on the program after it stopped working and I thought I screwed something up.

Just pop the bottom screw off and it will open. Maybe the contacts on the float came loose or a pin on top needs to be soldered.

[dmc6960]

Why don't you use a potentiometer instead of the actual sender?

Yea, for endurance testing (how quickly can I jump the needle back and fourth before it starts skipping steps?) this would be best. Its what I should have done in the first place. Still need to do full-up bench testing using the real sensors and senders though. This will ensure proper calibration of the input circuits and the program. I do still have a functioning original fuel sender on my car. It reads both full and empty, just not quite linear in between. Though who else with 130k+ miles can say they're still on their original eh?

[aipri]

A little late to the party here, but I just discovered this thread and must say thank you for this massive undertaking. I haven't even purchased a D yet, but I want this cluster, I hope you are able to get it completed!

[Bitsyncmaster]

Yes I'm going to get this also. My center console looks so good it makes the dash look like shi? at night.

[1batt4u]

What's the story on the electronic cluster?

[DMCSPRINT]

Hello I am installing Dave's LED ac panel and would like to modernize the instrument cluster as well. Was just checking to see whatever happen to this project? If your selling them how much? Thank you