SL/R129: help diagnosing hydraulic pump circuit (electrical)
#1
help diagnosing hydraulic pump circuit (electrical)
hi,
I have a 95 r129. the hydraulic pump does not seem to be working, and I looked for voltage on the connectors to the pump, but don't see anything.
Is there an electrical diagram of where that connector is fed? which fuses should I look at?
any help would be greatly appreciated.
I have a 95 r129. the hydraulic pump does not seem to be working, and I looked for voltage on the connectors to the pump, but don't see anything.
Is there an electrical diagram of where that connector is fed? which fuses should I look at?
any help would be greatly appreciated.
#2
SPONSOR
hi,
I have a 95 r129. the hydraulic pump does not seem to be working, and I looked for voltage on the connectors to the pump, but don't see anything.
Is there an electrical diagram of where that connector is fed? which fuses should I look at?
any help would be greatly appreciated.
I have a 95 r129. the hydraulic pump does not seem to be working, and I looked for voltage on the connectors to the pump, but don't see anything.
Is there an electrical diagram of where that connector is fed? which fuses should I look at?
any help would be greatly appreciated.
checking power to the pump is easy. The pump has a 4-pin relay next to it. Read the numbers on the relay pins after you have removed the relay.
The fuse panel in the trunk has a 40A fuse that supplies power to pin 85 on the relay connector. Check first if there is power to pin 85. The relay bridges pins 85 and 87 when it is activated. If there is power to pin 85, then you could jumper pins 85 and 87 briefly, to see if the pump will run. There is a lot of current going to the pump when it starts up, so you will see some arcing on the connectors.
If the pump runs, then the next step is energizing the other two pins on the relay and seeing if it works. If both the pump and the relay are functional, which is quite likely, then the next step is finding out why the controller is not activating the relay.
Klaus
www.tophydraulicsinc.com
#5
SPONSOR
Okay, the pump works and the relay works. This means the relay is not getting the signal from the controller to turn on the pump.
Let's check out the easy things first. Since you have a model year '95, that means the windows need to be "indexed" or synchronized. This applies to model years '95-'02, where the windows have to be down a little before you close the door, so that the upper window seal does not get crushed. The windows are properly synchronized if they drop about 1/2 inch when you open the doors.
Questions: do your windows go down about 1/2 inch when you open the doors, and what position is the top in now?
Klaus
www.tophydraulicsinc.com
http://www.tophydraulicsinc.com/en/18-r129-sl-90-96
Let's check out the easy things first. Since you have a model year '95, that means the windows need to be "indexed" or synchronized. This applies to model years '95-'02, where the windows have to be down a little before you close the door, so that the upper window seal does not get crushed. The windows are properly synchronized if they drop about 1/2 inch when you open the doors.
Questions: do your windows go down about 1/2 inch when you open the doors, and what position is the top in now?
Klaus
www.tophydraulicsinc.com
http://www.tophydraulicsinc.com/en/18-r129-sl-90-96
![](http://www.tophydraulicsinc.com/diagrams/r129diagram.jpg)
#6
Yes the windows are synchronized and drop down a little when opening and closing.
Presently the hard top is on the car. I had to manually lock it in with top wrench
Roll bar will go up and down with switch. Red light on top switch flashing and it dings for a few seconds when driving
Presently the hard top is on the car. I had to manually lock it in with top wrench
Roll bar will go up and down with switch. Red light on top switch flashing and it dings for a few seconds when driving
#7
SPONSOR
hard top, manual locking, roll bar, and rear lock for cylinder 1298002172
Yes the windows are synchronized and drop down a little when opening and closing.
Presently the hard top is on the car. I had to manually lock it in with top wrench
Roll bar will go up and down with switch. Red light on top switch flashing and it dings for a few seconds when driving
Presently the hard top is on the car. I had to manually lock it in with top wrench
Roll bar will go up and down with switch. Red light on top switch flashing and it dings for a few seconds when driving
the roll bar going up and down with the switch means that the pump and relay are good, anyway.
The chime going on when you are driving means that one of the locks is either not fully latched, or not giving the controller the latched signal. Let's deal with that first - I assume that there are other issues because you already had to put the hard top on manually.
Since you locked the hard top down manually on a '95, it might not be fully locked in the rear. '95 was a transition year, where some rear locks were delivered with the lever that allows you to lock and unlock the rear manually, and you can access them from the trunk without peeling the carpeting aside. Check out the schematic below. It shows the rear lock for the passenger side with only the short release lever, and the rear lock for the driver side with the early-model lever that allows you to lock and unlock manually (your locks would be black on a '95, even if you had the old style). Which version do you have?
![](http://www.tophydraulicsinc.com/diagrams/r129diagram.jpg)
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#8
I did not see any lever. I used the top wrench to lock, it fit on the two silver tab. Nothing looked like it could b done manually without tool
Last edited by larrytbull; 10-16-2013 at 08:08 PM.
#9
SPONSOR
locking and unlocking the rear manually
While the aluminum tab ("silver" color) is made for UNlocking, it can indeed help in getting the rear locks over the dead spot near the end of travel, while pushing down the rear of the top into the lock. The pictures below show how to get access to the newer style rear locks and how to unlock them with the tool (by moving the tab upwards).
Does it feel like the rear of the hard top is locked down firmly on both sides, without play?
Klaus
www.tophydraulicsinc.com
![](https://mbworld.org/forums/attachments/sl-class-r129/254755d1362671364-cant-lock-hard-top-92-500sl-rear-lock-instructions-1.jpg)
![](https://mbworld.org/forums/attachments/sl-class-r129/254756d1362671364-cant-lock-hard-top-92-500sl-rear-lock-instructions-2.jpg)
#10
I will check for that lever, didn't see it when i looked, I do however know it is down and not moving on either side
Will confirm again tonight
thanks for all the help so far
Will confirm again tonight
thanks for all the help so far
#11
SPONSOR
Here is how to test the front locks:
Put the 6-mm Allen wrench in one lock and turn more in the locked position, thus taking all the play out of the lock. Holding the wrench in that position, does the chime go away? If it does, then you have found the culprit. Do the same for the other side. If one of the front lock micro switches needs adjustment, then I will provide detailed instructions.
Klaus
www.tophydraulicsinc.com
#12
It looks like what you are calling a lever I am calling a silver tab, that is what i used to tighten back.
I used the wrench to tighten front and no difference when holding it as tight as it could go
still see the light on the switch
I used the wrench to tighten front and no difference when holding it as tight as it could go
still see the light on the switch
Last edited by larrytbull; 10-18-2013 at 09:50 AM.
#13
SPONSOR
Klaus
www.tophydraulicsinc.com
#15
SPONSOR
Nineteen out of twenty times, the trick I described (holding the front locks tightly in locked position) takes care of finding the problem. The chime means that one of the locks is not giving a locked signal.
Have the front locks been worked on before you started having trouble?
Have the front locks been worked on before you started having trouble?
#17
SPONSOR
Maybe it is time to take the trim panel off the windshield header and physically check that the micro switches on both sides are okay. Be careful not to damage the magnetic sensor in the middle - do not pull on its wires. See page 3 of http://www.tophydraulicsinc.com/R129...derslowres.pdf.
To compare or adjust the switches, see http://www.benzworld.org/forums/r129...-switches.html
Klaus
www.tophydraulicsinc.com
To compare or adjust the switches, see http://www.benzworld.org/forums/r129...-switches.html
Klaus
www.tophydraulicsinc.com