W124 cruise control not working

[JumboBeef]

I have just got my 1994 W124 E220 Auto Estate today, and so far I'm enjoying it! However, the cruise doesn't work (I did know about this before buying it) and so could someone please point me in the right direct to fix it.

I've already looked under the bonnet for the vacuum pipes etc, but couldn't see any. How does the cruise control work on this car please and what should I be looking for to fix it?

Thanks!

 

[PhilG]

I was investigating this on mine too, check out the MB service manuals on here:

http://mb.auto.pl/component/option,com_wrapper/Itemid,62/

I'm assuming the cruise on the E220 isnt any different from that on US models...

 

[JumboBeef]

Thanks, but I can't see where it tells me about vacuum pipes etc..............?

 

[JumboBeef]

OK, after lots of Googling, it would seem the fault is going to be with the amp, possibly dry joints.

Has anyone ever had sucess with remaking the solder joints on the amp? I have found a local computer shop who is willing to remake the joints at £25 per hour: do you think this would work?

Anyone got a spare one?!

 

[JumboBeef]

Anyone know what the part number would be for my amp please? 1994 W124.

 

[andy_k]

I'd start with getting the amp overhauled, that should be the cheapest option

 

[The G.F.P]

mine has gone too

works till 50mph then judders then by 60 ish the judders get so bad it turns its self off

my merc bloke tells me it needs taking out and a looking at and possibly replacing

mins been the same for 4 years

 

[JumboBeef]

I'd start with getting the amp overhauled, that should be the cheapest option

Thanks, but should I get it re-soldered at £25 per hour (could they do it within an hour, and would it work afterwards?) or buy another second hand one from eBay for around £40?

 

[andy_k]

the problem with a lot of these second hand units is that they will be in much the same condition as yours. Some will work, some may work for a few months/weeks and some won't work at all.

At least if you get yours re-soldered it will be probably outlast the car.

 

[JumboBeef]

At least if you get yours re-soldered it will be probably outlast the car.

Thanks, but will re-soldering fix the problem? I only know about the re-soldering idea because I read it on the interweb, and we all know how reliable that is

Has anyone out there actually had their unit re-soldered, and did it work?

Thanks.

 

[andy_k]

if it's just a dry joint (or several of them) then yes it will work - I 'fixed' the one on our old 230 like this - it took me a couple of hours or so to check/resolder it but I'm sure I could have done it quicker had I tried.

If it's any other fault, then no matter how much resoldering you do it won't have any effect. Sometimes DIY maintenance is just a process of elimination and this could either be the cure or the first step

 

[JumboBeef]

Thanks!

OK, so I got the unit out............now I need to decide if I'm up to resoldering it myself, or whether I'll wreck it trying to do it myself. My local PC shop will do it for me @£25 per hour.

Any soldering tips please? I have an iron with a fine point.

 

[andy_k]

get the iron hot and just place it on each connection - just enough to soften the solder.

A clip on heat sink/shunt is useful to protect the components as you solder them (I've got one of these you can borrow if you cover the postage each way ). Other than that, all you need is patience

 

[JumboBeef]

heat sink/shunt

Thanks for the offer but do you know, I think I have one of those in my tool box already, and I never knew what it was for

 

[JumboBeef]

One question before I start: what do dry joints actually look like? All the joints on the board *look* OK to me, but is that normal for dry joints?

Do I just do them all, starting from one end to the other? I was thinking of not doing the IC joints (worried about heat on the IC) but doing all the others and only if the cruise doesn't work after that, then do the IC joints.

Is this a good idea?

Thanks!

 

[andy_k]

a dry joint will normally be invisible - the solder breaks away from the contact inside the joint which is why you need to soften all of them thus forcing the solder to remake the connection.

I'd start at one end and work my way along marking the board as I went along - any joints you are worried about, use the heat sink. Once the iron gets hot enough you'll only be making contact with each joint for a couple of seconds

 

[JumboBeef]

Well, I took the bull by the horns and got my soldering iron out. Remade all the joints, put it back in and............



















..............it works!

Thanks to everyone who help, particularly andy_k

 

[mattc]

thats a nice result!

 

[andy_k]

nice one

 

[Ade B]

Hi all

My cruise has gone intermittent, soldering is sort of in my skill remit so could anyone direct me to the aforementioned Amp unit on an early M104 for my CE24V so I can give it a prod.

Quick search didn't throw up any links..

TIA

Ade