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89 560SL Over Voltage Protection Relay - not available 2015400845

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10K views 52 replies 15 participants last post by  Martin_fromGermany  
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#1 ·
1989 560SL (US)
The only direct matching OVP (part number 2015400845) I can find for sale is on eBay for $599. Even Pelican Parts lists it as unavailable. Called the local dealership and they said they have two part numbers for this - 2015400845 and 1265404745, but they are both unavailable and discontinued.
I've found listings for part number 2015403745 which state this will fit my car, but thought I would check with the hive mind first.

The symptoms I'm having is intermittent sine-wave like idle where the idle at rests goes up and down with a regular rhythm, and occasional misfire /sputtering while driving or idling. I also had one episode of difficult cold start (typically always starts right up) which was followed by stalling and misfires so bad I turned around after 2 blocks and came home. Started and ran fine the next day. Last night, started experiencing steady idle speed of a little over 1k. Today I went out and it started and idled fine. Pulled the fuse on the OVP and while the loop is intact, there is some carbon or corrosion under the plastic on the top of one of the blades (see photo). I can't imagine how this would affect anything, but going to pop a new fuse in anyway. Figured if it wasn't too expensive I'd just replace the relay - and that's what brought me to where I am now. Any other diagnostic suggestions welcomed!
Image
 
#5 ·
Looks like something that can be reverse engineered quite easily. I know the circute boards can be made for about $50 for a qty of about 5. It's also a part that I would expect MB to start making again once the Covid backlog settles down.
 
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#6 ·
My OVP is only 6 pins, one of them a plastic dummy.
UPDATE: I put a new fuse in and put the relay back in place. I could just be imagining it but it seems to be running better. No misfires, stalls, near stalls, or rough idle. I’ve only driven about 5 miles though. Could be coincidence. It doesn’t make sense a fuse which still conducts but has some damage could effect how well the car runs (but sort of like Santa Clause - I just want to believe).
 
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#20 ·
Plinker - I truly appreciate all your help. AutohausAZ is also out of stock, which might be why it says the part won't fit my car. Right now my high idle is gone (it's oddly intermittent) but my ABS light is on. I pulled the relay, opened it, and re-soldered all the points, put it back, and the ABS light is still on. I feel like I've pretty much ruled out the relay as the cause of the idle as well as the ABS light at this point, so I'm moving on to replacing the idle control unit and looking at the ABS light as a separate issue. Wish me luck!!!
 
#24 ·
Michael Williamson Plese read .

The forum index is organized / grouped according to chassis designation, usually a letter followed by 3 digits / numbers, and sections cover all engine / versions the chassis came with.

To find the forum section = chassis for your car, please click FIND YOUR FORUM SECTION
Head on over the chassis forum and post your Q.

And whn you do acquire your ride, Complete your Profile by adding the year and model of your car, so it will show next to every future post under your avatar.
Members are not likely to search for the one post the model of the car is mentioned.

The forum section archives have a wealth of DIY / technical information.
When researching an issue / posting, you can also Search the forum archives of your chassis section via the 'Search Community' box on top..

The stickies on top of the 'Welcome' section will help to navigate the site.
 
#26 ·
I have an 82 380SL. I was told by a local mechanic shop that specializes in vintage Mercedes that a new OVP would help my low power issues. I asked The SL Shop if they agreed and they said they were not aware of that. I hate to spend nearly $500 to find out. Anyone here have thoughts on this subject? The car is running well after a year+ of slow restoration from sitting 10+ years. Freeway on ramps and even slight hills are difficult even with the gas peddle to the floor. Runs fine when flat and level.
 
#27 ·
Is your idle speed ok, i.e. around 650 - 700 or so? If so the OVP is ok as it also powers the idle speed system. If the idle system is not powered the idle speed will be around 1100 -1200 rpm. The OVP also powers the "lambda system" which makes fine adjustments to the fuel mixture - but not a likely cause of what you describe.

Low power can be a number of things, blocked cats, incorrect fuel pressure, incorrect timing, vacuum leaks, even the transmission shift points - if too low this can give the illusion of low power as there isn't much to begin with.

Did your local shop actually check anything or did they just give you an opinion?
 
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