R129 - Serious electrical problem… grounded until fixed! - PeachParts Mercedes-Benz Forum

Rud · #1 06-14-2009, 08:15 AM

The electric system has just gone berserk. It started some time ago, when activating the turn signal, all laps in the instrument cluster blink ones, and power to the radio and navigation disappeared for at few seconds. This happen a few times, but with weeks in between.
Then the other day, a new strange thing happened. Suddenly the ASR and ABS lamp was constant on, and every time I pressed the break pedal the roll bar lamp turned on to, as long the breaks was activated.
Then yesterday it culminated. Nothing works in the instrument cluster. No instrument indications of any kind, except that all lamps are blinking. Strangely enough, when I flip the turn signal arm the blinking stops, but the turn signal lamps don’t light up. The indoor light at the top of the windshield doesn’t work either, but the ones in the doors are blinking every time I flip the turn signal.
I have checked all the fuses, both in the front and in the trunk. And I have moved them forth and back, just to make sure there are connections.
So, what’s next? Any idea where to look for a broken connection, bad relay or ground connection, controller unit… anyone else that have experienced the same strange behavior, and knows what to do?
Rud

waybomb · #2 06-14-2009, 09:05 AM

I had all sorts of goofy electrical issues when my OVP failed. Maybe the OVP?

tecqboy · #3 06-14-2009, 11:25 AM

Possible bad voltage regulator on VDO ( cluster )? Search the forum on "capacitor" and cluster / VDO. There is a capacitor which fails and causes some of the problems you listed.

Rud · #4 06-14-2009, 11:29 AM

I have managed to get things back, to almost normal, twisting all fuses ones again. Now, only the ASR and ABS lamp is on and the top can't open.

I have tried to locate the OVP, but without succes. Under the alu cover the are four 10A fuses, all okay as well. But the OVP, really can't find it.

There use to be a item locator at www.classic-roadster.de, but that site has been down for quite awhile. Anyon know if this has been moved to somewhere else?

Rud

Rud · #5 06-14-2009, 11:34 AM

Quote:

Originally Posted by tecqboy

Possible bad voltage regulator on VDO ( cluster )? Search the forum on "capacitor" and cluster / VDO. There is a capacitor which fails and causes some of the problems you listed.

Thanx tecqboy ... If it turns out that it isn't the OVP fuse or OVP itself, and a general reset doesnt fix the problem, I will start look for that hit. As a matter of fact, I have to have the cluster out anyway, because the bulb for the outside temp are dead. Wonder if these 0,75w bulb can be replaced with LED's instead.

Rud

Rud · #6 06-14-2009, 11:46 AM

Somewhere else I saw a statement from you, that 200.000 miles i near the end of the R129 engine. Mine has run for 156K miles, and is perfect. No oil loss etc… except I have to replace the distributors and rotors. It's common over here to say, that a Mercedes engine is worth 625K miles… I hope you're not correct in your statement ... I just love that car

tecqboy · #7 06-14-2009, 12:19 PM

I don't believe I've ever made a statement in the forum regarding the life expectancy of a Mercedes engine. I have no personal experience to make those judgements. On my '91 129, the OVP is under the hood on the right side near the fire wall under the plastic weather seal which covers the electronic modules. I believe there are 4 or 5 screws to be removed to gain access.

suginami · #8 06-14-2009, 01:17 PM

Is this 129 a six or an 8 cylinder?

Only M104s have OVP's. M119 V8s and the later M112 or M113 V8's do not.

Rud · #9 06-14-2009, 01:36 PM

Poul its the 119... the probem is, that Im not sure what I'm looking for. I have located a connector with 3 legs, an long kind of pipe, could be a connector as well, around a wire, and then some other connectors which are mounted on a rail. But I can't identify any relays.

Maybe you're right, the 119 don't have the OVP relay and fuse... tomorow, I'll let the Idy look at it, at least make the reset and see if that itself will fix the problem.

Thanx for your reply

Rud

LeaUK · #10 06-15-2009, 09:57 AM

You may find this interesting?

Flashing Instrument Panel on ignition pos 2?

Rud · #11 06-15-2009, 03:40 PM

Hi All,

Thank you for all your good advices. This evening I went to the Indy, and on my way out there surprisingly everything worked okay, except I still couldn’t open the soft top. So, at least the Indy could reset this function, since non of the other things: flashing lamps in IC, constant ASR and ABS light, and the roll bar light coming on every time I press the break pedal, no turning signal etc… had disappeared. Even more embarrassed was, when I, just for the sake tried the soft top ones more at his parking… and now working perfectly

Fortunately a Kleemann mechanic showed up at his place while I was there. His best guess, when he heard about my problem was… the OVP. When I claimed someone had told me that the 119 engine don’t have a OVP relay, he said that every Mercedes R129 has one and he opened the hood to show me. Well, well, not to be found anywhere. A big mystery…

So who knows a 119 engine, a 500SL V8, 1993, and where to look or at least know a part no. ?

Rud

suginami · #12 06-15-2009, 05:50 PM

M119's have never had an OVP. I believe the base module replaces the OVP on this engine.

bobterry99 · #13 06-15-2009, 10:54 PM

All CIS-injected cars have an OVP. For MY1993 the V-8 cars switched to LH-injection; and as Paul said, the Base Module essentially replaced the OVP. Like the OVP, the Base Module has fuses on top that should be checked.

per · #14 06-16-2009, 02:48 AM

Hei Rud.

See the following on wiring harness:

http://www.benzworld.org/forums/r129-sl-class/1304844-unresolvable-problem-even-merc-dealers.html

http://www.benzworld.org/forums/r129-sl-class/1433155-newbie-needing-engine-wiring-harness-93-a.html

Regards, Per

Rud · #15 06-16-2009, 09:19 AM

Alright the base control unit. Suppose that is the one inside and back of the alu box with four 10A fuses. I tested those in the weekend, and all seemed okay.

Per, you scare the

out of me, talking about a bad harness. I really don’t hope this is the case. But of cause it will be on my mind, if everything else has been tested okay.

I suppose the base control unit is much more expensive to replace then the single OVP relay. By the way, looking at this site: www.k6jrf.com/MB_BM.html, knowing it’s for the S500, I can’t read anything about overvoltage protection. Can be my ignorance… but if correct, I still need some OVP relay somewhere.

Rud