90 SL300 soft top problems - Benzworld.org

Canex · 05-08-2008, 04:08 PM

Hi all ,
1990 300 SL was working fine then flat battery. Replaced battery - sun came out - remove hardtop - night came - raise hood - problem!
The deck was trying to raise one side OK - other wouldn't move - then both raised OK. BUT hood wouldn't lift!
If I lift it manually it works fine - locks - even folds away as good as gold - but it won't lift after the deck has gone up.

I have read all the threads I can find and have tried all the suggestions:
read the fault codes - reads 1 - all OK
reset the codes
reset windows & roll bar (10 seconds at each setting)
uncoupled battery for 10 mins
No hydraulic leaks
Level of fluid is fine

everything works Ok apart from the 2 main hydraulic rams won't push the hood up!!!!
There must be something telling them not to work
PLEASE HELP !!
does anyone have the hydraulic/electric diagram for the hood so I know where to start looking for a faulty sensor/relay/bypass valve/ram ????
I am not sure it is to do with the battery being changed, the pump is running & there is movement from the hood when it is trying to lift and relays clicking - but if it is stopped when folding down it cannot raise again & will still fall with gravity even if the switch is being held on.
Please someone save me from certain insanity !!!!!!!

Chris

Canex · 05-09-2008, 06:01 AM

Does anyone know if the repair DVD can be bought in the UK? I have the WIS programme but find it almost impossible to run (I have it on 3 computers & it doesn't seem to work properly on any of them)
I am still looking for help to find which relay/pump etc powers the main two cylinders to raise the hood up. It has a number 70 on the hydraulic pipe from the cylinder but I can't see where that goes to?

cheers
Chris

**RedLiner** · 05-09-2008, 08:28 AM

Chris, I have looked on my Alldata CD's for your year and model R129.

There are plenty of electrical diagrams but they would take up pages of forum bandwidth to screen grab and post them up, likewise with the hydraulic info.

There is a topic on how to obtain the Alldata CD's just search for Alldata.
If you can point to a specific part of the circuit diagram I will try to find it and post it up. Looking at the hydraulic diagrams I could not see any reference to a pipe Nº.70.

I'm sure that when our soft top experts pick up your post they will comment, unfortunately sometimes these members are not always available to answer queries straight away.

mhabie · 05-09-2008, 08:40 AM

Just a helpful hint about Alldata. I don't know about the UK, but here on Long Island,NY, you can go into a library in the reference center and access their computer with Alldata on it for free. Free printing for 5 pages, and then 10¢ a copy.

Canex · 05-09-2008, 11:44 AM

Thanks both for that - I'll try searching for an Alldata CD over here.
I must admit I already have the WIS - but find it a real pain to work & not very user friendly when it finally does!
It's great - finally get a couple of sunny days over here & I'm driving around with the back missing out of my car!!
cheers
Chris

bobterry99 · 05-09-2008, 09:43 PM

The hydraulic line you mention goes to a valve block Chris, (picture). Your car has two for the convertible top, and each has four solenoids. Power to the solenoids comes from relays located within the top control module.

Its possible that a problem with a relay or a solenoid is preventing your top from moving. But I believe it is far more likely that the control program hasn't progressed to the point of raising the top because the limit switch that detects when the compartment cover is open has a problem. This would be confirmed through diagnostics or by checking the signal from the switch with a basic electronic multimeter. You mentioned that no codes are set. But at the point motion stops if you continue to hold the switch long enough (up to 90 seconds) it should begin to flash -- this indicates a code is stored.

Canex · 05-10-2008, 12:51 AM

Thanks Bob, I'll go and try that now - I didn't hold the switch on for that long - I thought it might strain something!
I also haven't taken that side of the rear cover off - I thought there were only relays on the other side. I must try & get my WIS programme working!!
thanks again
Chris

Canex · 05-10-2008, 02:56 AM

Hi all, thanks again Bob

- held button like you said & after 90 seconds finally got a code - 15
I have found out that code 15 means: limit switch soft top up (secondary closing speed)
Does anyone know what that means? or where the limit switch is situated?

It's almost exciting now!!

cheers
Chris

**lynns** · 05-10-2008, 07:25 AM

I see that Bob Terry has already been helping you but you may want to read the lower half of the page at http://www.benzworld.org/forums/r129...te-thread.html

Canex · 05-10-2008, 10:47 AM

Thanks Lynn,
I have read them all at least twice - they are incredibly usefull

- it's amazing that Bob Terry seems to have the answer to every problem!! I hope he can help me find the answer to mine!
I would like to say it's nice to get help from people you don't know, from all over the world! - I hope I can be of use to some of you in the future - I only seem to visit these forums when I have a problem

Out of interest have any of you got the cassette that came with the cars when they were new explaining how every thing works? If not I will try to get it on MP3 & post it.
Cheers
Chris