Cruise control amplifier on 124 (1990 300E).
 

Where is it? I have been told by many that this is my problem. I took all the covers and carpet from the driver's footwell and can see under the dash but I don't really know what this item looks like.

Its an aluminum enclosed module. Measures about 6" x 4" x 1.5" with a black electrical connector on one end. I am not sure on your car but they are generally located near the steering column by the drivers feet under the dash.

Thanks, Dave. I'll have another look. I was actually looking for something smaller.

Found it and the new one is on the way. Hope that's the problem but if it isn't, it would have eventually gone bad. Thanks.

Send me your old one. I can fix them. I can send you a fedex shipper so it will cost you nothing.

Dave, how much to repair if I send you mine? I am not certain this is the cause of my dead cruise control but figured it's worth a try.

Nothing. Just freight.

Do you have any suggestions on things to try before sending them out? If you really want to do more of these, I'm sure you'll get plenty of people offering to provide their units (myself included).

I have consulted resources, including my "124 Bible" and cannot figure out how to get my amplifier out from behind the dash panel:o

It appears I need to pull the lower portion of the panel directly under the steering column, but, no joy yet! Any tips from those experienced in this procedure?

is the amp. the problem if it starts surging while the cruise is on, my unit will work great for a while then start searching like it can't hold the throttle, if this is it you can check mine also as I don't have the money for a new one, thanks richard

Dave. As soon as my new/used one comes in I'll contact you. Do you have a way to test the unit itself? I'm reasonably certain the one I bought will be good but if the CC doesn't work after I install it I'll need to figure out where to go from there. As an aside, what can a person do with a vacuum block (behind the glove box that routes vacuum to the climate control doors) that has apparently gone bad after only 9 months? Is there a fix or where can I buy one at a reasonable price? Thanks for your time. Chuck.

Those vacuum valve blocks are fixable - sometimes. I have had them "suck" dirt into the valve orfice which is very small. A good blow job in the appropriate areas sometimes will recover them.

As for the cruise control amps. I own 4 of these cars and all of the CCA's have failed and I was able to re-solder them and they all went to working. I dont have a way to bench test them. That would be ideal, but in every case for me it turned out to be the weak brittle solder joints that failed as a result of vibration over a long time.

I spend about an hour messing with them as there are several hundred joints. I have an electronics shop and a stereo microscope and you can see the problem joints. I resolder all of them regardless of how they look. The joints in question are always on the larger components which are more affected by vibration than the smaller parts since the parts are suspended by their leads soldered to the board.

I should rethink my offer to repair these. I could see a flood of these things ariving at my door and then I would never be able to retire. Also I cannot guarentee results since I cannot test them without putting them into a car. So in some cases the amp may not fix the problem

Lets try this. I'll charge $35 for reworking the module plus actual shipping. No guarentees on outcome. I will guarentee that the work is first class. These things are not very big or heavy so the return shipping should no be too much - probably $5-9 depending on distance UPS ground. I'm guessing on that rate.

Let me know what you think. Open to other suggestions.

BTW I have repaired just about all the various modules in these vintage cars except the EZL ignition module because the EZL is potted in epoxy and I cant get into the thing.

I will send you mine if you think the amp is my surge problem , thanks richard

Anybody?? BTW, it is an '87 260E

I would bet money on it.