There is no light indicating it is engaged.

Just the light on the button when you turn on the vacuum pump.

Mine recently died and I am watching this thread with interest. Gotta get under the hood and check out the vacuum lines, pump, and bladder.

I have a D2 CC ECU ready when all that stuff checks out ok.

 

Easy way to check the bladder is to pull the vacuum hose. Compress the bladder with your hand. Firmly press your thumb over the nipple where the vacuum hose goes. If thw bladder stays compressed its good. If the bladder slowly inflates it's bad.

 

Well, I decided to just go on faith and replace the ECU (even though my disco seemed to fail a few of the tests listed).

I had the AMR5700 sitting around that I got off ebay without a pigtail for $7. I decided to pull the connector off the old ECU module and used ribbon cable from an old computer harddrive to wire the old ECU connector to the new ECU.

I didn't have high hopes of it working because my car had failed a few of the tests in the beginning of this thread, but low and behold, after plugging in the new ECU, I took the truck for a spin and I'll be damned if my cruise isn't working now...

It wasn't quite as easy as just replacing the ECU though. I ordered 8 feet of 4mm silicon vacuum tubing off ebay for $8 shipped replaced all of the vacuum lines in the system. I got lucky and my throttle bellows was still good.

I had to do a little work on the brake pedal vacuum switch, though. It would not hold vacuum. I took the switch apart and cleaned it out as best as I could and reinstalled it and it was not holding vacuum still, so I took some aluminum foil tape and cut it into 1" x 1/2" strips (probably about 10 - 15 strips) and one-by-one stuck them onto the spot on the brake pedal that the switch makes contact with - essentially building it up so that it would push the brake switch button in a little further. And then after that, the switch would hold a vacuum.I'm wondering if my brake switch was maybe missing some sort of a rubber end or something.

So anyway, all told and $15 later, I have a working CC system again. Woohoo!


One observation I've made though is that the RES (-) button cancels the cruise - very similar as if I were to put my foot on the brake.

I'll post up some pictures later if I get time.

Thanks again for everyone's help!

 

You can take the brake switch and pull out on it. Then when you re-install it make sure the pedal isn't anywhere near it. When you release the pedal it will automatically adjust itself for the proper spacing. I'm pretty sure internally there is an o-ring to keep it air tight.

 

Here are some pictures. This would have been a lot easier if I would have gotten a module with a pigtail, but since any of those were a great deal more expensive, I just picked up one on the cheap to play around with.

The first thing I did was to de-solder the connectors - which was infinately easier on the old 1173. Then I grabbed an old ribbon cable from a hard drive and pulled off 10 wires from that and frayed them about and inch and a half from each end, stripped and tinned each of them. Then I soldered them to the new ECU board and labeled them with a tiny sharpie. next I soldered the wires into their respective places on the old connector. after it was all soldered up and a test drive had been completed, I wrapped the new ECU (which is considerably smaller than the old board) in a plastic sandwich bag and stuffed it into the old container, and secured the connector back onto the container as well. The connector had to be affixed to the black container cap, which I did by putting the connector into the cap and then drilling small holes thru both pieces and then inserting small nails into those holes to "pin" the two together before I re-crimped the cap into the container. Unfortunately I forgot to snap pictures of these nails holding the two plastic pieces together.

 

Nice, looks sano!!!

 

I'm starting to wonder if splicing the new module to the old pigtail is actually more work than just replacing the connector under the glove box. I do understand that it is an awkward place to work in, but for such a non-essential item I might simply live with 'crimp' type wire splices rather than soldering.

 

It took me no time at all to cut off the old harness and splice in the new pigtail! It wasn't like working on a work bench, but it was certainly do able. Probably took me 30min from start to finish. I used some of those 3M inline splice connectors with the heatshrink on them and then just used some wire loom. I prefer that setup myself vs hacking the old CC ECU up, but that's me.

 

I did this job recently using a ECU from a D2 which didn't have the pigtail. I wish I would have gotten the pigtail but made it work fairly easily nevertheless. I more or less did what notny did above except I purchased a generic 20 pin ribbon cable connector from an electronics store and a short color coded ribbon cable. After cutting off the D2 units socket you can plug the 20 pin generic connector into the 18 pin jack. The ribbon cable connects and then there is no soldering required on the new unit. My solder skills are good enough to solder to the old unit's plug but didn't trust myself on the 18 pin connector. Works good.

 

Thank you for this writeup! Fixed my '95 today, cruise works perfectly with the new ECU. I made the adapter from the old ECU plug.


Took the window lift ECU out and resoldered it too - now my back windows work all the time too. A good day in Discoland.


-Kevin