Mercedes OVP Relay Repair 2021 & 4K

I found this in the shed and decided to refurbish it as a spare.

[@Johnathan_Waters]

Beautiful new solder joints (even though there was no flux!). I didn't know about the Zener in these! Thank you.

[@w124mercedes7]

I have found most switches and relays are easily repairable with solder or 2000 Grit sand paper. I was able to take apart all my window switches and clean the contacts inside and now work like new.. same with relay . Clean the contact points and often its all they need. Better than buying new.

[@RoryLock-m6c]

Thanks MMWA, class act, love your videos and help.

[@opelromantico9335]

Great job and video, nice work and explanation about how it work and measurements.

[@chrisromanczuk1468]

I always keep an extra in my trunk. These relays get a ton of crap but they are pretty incredible.

[@williamkennedy5492]

Thank you, this afternoon i have just located this relay on my 1990 R129 300-24 SL , the car does start but tries to idle at 350 rpm, then dies, after the 4th attempt and by tickling the throttle you can get it to idle at 900, BUT it will increase rpm to 1500. This relay is the culprit, not the idle control valve. I think first steps is to order a new relay from Autodoc , i will when i receive the part take the old relay apart like you have shown, my dc controller is currently in Sisaket Thailand and i am back in the UK Cheshire .. Thanks for the video.

[@bernardwarr4187]

Very informative, many thanks

[@TheUnreal1982]

Thanks bro. So nice. 👍

[@apexseal2811]

I was always curious about what could be the culprit of a bad OVP relay, considering it’s a (quote) “high rate failure component”, as ownership experience shows in most cases. A brief google search allocates the fault shared between the Zener diode and cracked solder joints due to heat, as stated in the video. So, another component which will eventually require maintenance.

[@MMWA-DAVE]

i should have also mentioned in the video, the telltale sign of the ovp failure on cars with ABS fitted is that that the abs malfunction light will stay illuminated in combination with the hard starting issues.

[@ironkcoony]

Perfect timing. I have a 300e coupe, in the summer I got ASD, automatic limited slip differential, light. Blinked the code, was saying break switch. Deleted the errorcode, light didn’t come on half of summer. A few weeks ago I was driving onto a parking lot when sudently the engine died. Car never did this before. Managed to restart right away, but ASD light came on right with restart. This time I am not able to get the error code, light is burning, no blinking mode. After some reading I found in case of strange behaviors of electronics, OVP Relais often is the culprit. Anyone similar experiences?

[@truthquest4791]

Are both relays interchangeable? I have a 93 190e.

[@cnstars124]

Nice work on your electronics and component maintenance/insurance. Your viewers could check to see if their engine was in lambda mode/closed loop easy enough with a voltmeter. If in closed loop it would indicate ovp were ok. This would be about the same as checking duty cycle and the ovp would have to be installed.

[@MMWA-DAVE]

Yeah. I might make a video showing the round diagnostic socket and what each pin is for.

[@saramima9101]

شكرا جزيلا

[@alanOHALAN]

hi, I broke off the sucket wire (it has 2 wires) off the number 30 pin I think. Why does it have two wires for one pin? Can I just twist the two wires and put them back to the sucket with a connector?

[@joonaspulkkinen6369]

AVOID CHEAP ONES. Ordered a new MB genuine one and in the meantime bought a Trucktec to get me by until the original MB part arrived. Well that lasted two days, 3rd day came to a empty battery. Problem: something jammed up inside and the ignition was on all the time even though the key was out of the lock. Original MB part for my car was about 140€.

[@joonaspulkkinen6369]

HFM car and original relay to the car had sometimes issues turning the fuel pumps on. So it caused a intermittent no start.

[@salehfiras943]

can you give us the part number for that plastic covering ?

[@MMWA-DAVE]

@@salehfiras943 there is no part number on it. maybe its in parts manual

[@1unsung971]

What does OVP mean?

[@MMWA-DAVE]

OVP is over voltage protection

[@EIRK2046Y]

Overvoltage Protection

[@saramima9101]

شكرا جزيلا

[@stevenkerr1455]

I’m in the middle of restoring it. @the_boddington_beast