OVP relay... took it apart, ugly! - PeachParts Mercedes-Benz Forum

LandYaghtLover · #1 11-01-2011, 11:40 AM

Took my OVP relay apart. I dont trust a single electronic thing on these cars. They may have been built well, but the electronics sure suck. So I have been on a mission to re-solder everything I can get my hands on!

After reading some threads I learned about the OVP relay. It basically is there to regulate power to some critical systems and insure that voltage does not run high. If a part, such as the brain box, gets to much voltage it may mis-read a sensor. This can make the car perform poorly or inconstantly.

The OVP is a very, very simple little relay. Its near the brake booster between the two firewalls. Typically there is what I call a "U.S." style 10 amp fuse under a clear cap that you squeeze to pop open.

To take it apart I removed the fuse that bend back the soft aluminum tabs on the bottom. With a pliers I gave a quick tug on one of the pins and it slide out. Note that there is a white plastic shield that needs to be placed between the board and cover when putting it back together.

I did take one quick pic. Based on outside appearance all seemed well. But clearly when opened, there was much corrosion. I think I will replace this with a new one when I have time. For now re-soldered the board. And to help with the corrosion, I soldered the pins to the plates where I could. You can see this on the left front. Takes a lot of heat and a while to heat up that metal! There is one in the center of the relay that was in very, very rough shape. I had to heat it from the pin side at over 600 degrees to get solder to melt on the plate side.

I am not sure if I had/have any issues related to this replay. But I feel a little better cleaning it up. Like I said, I place to replace it though.

JohnM. · #2 11-01-2011, 08:54 PM

Hirnbeiss · #3 11-02-2011, 06:20 AM

There were pieces from the Titanic that looked better than that.

LandYaghtLover · #4 11-02-2011, 03:55 PM

OMG. That is bad!

Ivanerrol · #5 11-02-2011, 07:28 PM

O.V.P. is just a Zener Diode, relay and a fuse or two - depending on variation.
You are really better off buying a new one - they're relatively cheap.

F.P.R.'s E.C.U.'s etc are all subject to extremes of heat and cold plus dampness. Any wonder that they start to misbehave after twenty years plus.

You average consumer computer electronic product would have died long, long, long ago id subject to the same ambient conditions.

LandYaghtLover · #6 11-02-2011, 07:42 PM

Quote:

Originally Posted by Ivanerrol

You average consumer computer electronic product would have died long, long, long ago id subject to the same ambient conditions.

True. But I have had older cars with electronics that have had no issue. It seems the solder used is sub-par. I wonder if there was some euro environmental regulation in place that prevented using a particular solder or whatever. Something was may have been ok in the states to use for manufacturing.

But the solution of re-soldering is typically fast and free. So I guess we can not complain too much.

Adler · #7 11-03-2011, 12:10 AM

The Zener diode can develop a cold solder at the joints or even a break under jump starting condition. Re-soldering gets it operational again . The Red fuse stays good .

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Ivanerrol · #8 11-03-2011, 05:02 AM

Quote:

Originally Posted by LandYaghtLover

I wonder if there was some euro environmental regulation in place that prevented using a particular solder or whatever. Something was may have been ok in the states to use for manufacturing.

Lead Free solder for example?

Lucky the electrics are not Lukey - The Prince pf Darkness