swmic

I recently experienced a problem with my power top. I would press the switch to open the top and nothing would happen. I couldn't find much on this type of problem on the archives so I thought I would right up what I found and post some pictures.

I started by checking the fuse and some of the micro switches, all of which turned up fine. Having the repair manual on CD, I noticed a part called the convertible top control unit. I suspected the problem might have something to do with the unit but I had difficulty locating it. I finally located the control unit under the drivers side footwell, sort of under the dash vent.

The part was a real pain to get out since it located on top of another electronic box with a VDO label on it. Once I finally got it free, I tried opening the top while pressing on the 4 connectors going to the part. To my surprise the top started moving. I thought great, it was just a loose connector. I reseated the connectors and tried again. Nothing moved. I tried again pressing on one of the connectors and the top moved again. I then knew it was probably a cold solder joint on one of the pins on the pc board or a bad connector. The control unit is housed in a plastic case which comes apart easily. Looking closely at the one of the connector pin solder joints, it was easy to see where the problem was. There was a crack in the solder joint around one of the pins. I heated up the soldering iron and reflowed all the solder joints on the pins adding a little extra solder. I put things back together and gave it a try. Now the top works great. The best part is that the total cost was $0.00.

I'll try to attach a couple of photos. They are the control unit with and without the cover on plus a shot of the area where the cold solder joint was.

Hope this helps.

Shawn
96 C4 Cab

hn

Thanks for posting. I was asked about the control unit before but didn't know where it's located. I believe your post is the first that shows the problem generated from the control unit. Another valuable info goes to my library

Thanks

upshift

Fixed it for $0.00!!!

I love to hear those stories.

nile13

German automotive OEMs can't solder, period. And VDO is the leading offender.
Ask me how I know. Or better yet, don't.

911MSN

i got the same problem this morning and found this... I rushed home from work, after cutting the day short, only to find out that it now works... it probably is the same issue as yours.

cabrio993

This was happening to me intermitently until I did this DIY and so far so good. Mine would go 2-3 days without working and then all of the sudden will start again. Typical poor or loose connection issue.

It has been now a couple of weeks since I re-solder all the suspected joints and the top has been working like a "top" (no pun intended)

Mike J

Germans are not the only ones who have cold solder joints. My wipers on my Chev pickup were acting very wierd, sometimes working, sometimes not. I was ready to by a new control module (~250 bucks) when my friend with the same year truck said "Oh, they all do that. Its a cold solder joint". He told me where to resolder the board and voila, its been three years and works great!

Cheers,

Mike

H20NOO

I had a similar problem recently and traced it to the microswitch on the emergency brake. There is a copper conductor that attaches to the back of the brake arm under the center console. It had come loose and lost contact with the switch. A little epoxy and patience and the problem was solved.

I was pretty happy not to take it in for an expensive (and often innaccurate) diagnoisis and repair.

MC

911MSN

ok, it's bad now. Since my top have stop working while it was in motion, i had to close it manually now and did. I had my dealer remove the part in question. Because they do not "fix" the unit and wanted to replace it with a new one ($950 for the part and labor), i told them that i'd fix it myself (the unit, that is). I spent 10 min fixing all suspected connections at their driveway (i had 2 bad one that i can tell by looking at it). they installed "my fixed unit" and it now works. Because i had close the top manually, they need to perform alignment on it and the car will stay at the dealer.

at leat i saved about $500 by looking at this site. thank you.

InTheAir

Nicely done, Shawn.

Thanks for sharing with the rest of us. It seems like it might be a matter of time before many of us have to deal with this.

ljugete

That's Great! No one (Dealer) wants to fix anything anymore, it is always replaced! Go figure?
This is a refreshing and eye opening post. I will certainly consider doing this before having to replace this unit.

pchak

I'm ready to go after this same gremlin in my car now. Any suggestions on how to dig the unit out from under the dash?

I'll follow the rest of the instructions, so graciously illustrated.

thanks!

swmic

Thanks guys! Mine has been fine now for over a year. I had one rennlister mail me his unit for a quick resolder. It fixed his problem also.

Suggestions on how to get the unit out? Find your nearest 6 year old, and hold the flashlight for him/her. If I recall there is only a couple of plastic nuts holding it in place. Its just a real pain getting in there.

John Hopkins

Shawn, Thanks SO much for posting this! I had this problem about a year ago and my service guy replaced the control unit at a parts cost of over $400!! Wish I had looked here! Well, the "new" unit has been intermittently failing for the last few days and did a quick search here. Had him pull the unit, and brought it back to my office where we have a great circuit board tech, he repaired the several cold solder joints and BAM - it works like a dream.

I just wish I had read this post last year before dropping the $400! Oh well, live and learn - anyway Thanks again!

...John

TheOtherEric

Yes, many of us have Shawn to be thankful for. He saved me $400 too!