Relaying a relay question 87 TD - PeachParts Mercedes-Benz Forum

Aquaticedge · #1 03-02-2010, 08:33 PM

My car's managed to blow something and i'm hoping something simple. long story short, I ran the car up to pakmail (local fedex place) ran fine, everything worked but the shifting issue.. turned the car off and overnight-ed something, came back and the Tach is dead, the car sounds like it's running on like 4 or 5 cylinders less power then it had... Place here says its some overload relay (???) my Antilock light is on (one next to the SRS on the left) Any thoughts?

charmalu · #2 03-02-2010, 10:51 PM

Might this be what you are thinking about?

http://www.allpartsexpress.com/ShopByVehicle.epc?q=1987-MERCEDES--BENZ-300tdt--/--L6--998cc--3.0l--Diesel--Fi--Turbo-Electrical&yearid=1987%40%401987&makeid=MERCEDES+BENZ%40%40MERCEDES+BENZ%40%40X&engineid=1194353%40%40300TDT++%2F+L6%2D2998cc+3%2E0L+DIESEL+FI++Turbo%40%40300TDT&catid=Electrical%40%40Electrical&subcatid=Overload+Protection+Relay@@Overload+Protection+Relay&mode=PA

Charlie

Aquaticedge · #3 03-02-2010, 11:36 PM

I dont know, I dont even know how to Check to see if it's working or not... it looks like a relay I've seen near the battery though

Jeremy5848 · #4 03-03-2010, 12:02 AM

Quote:

Originally Posted by Aquaticedge

I dont know, I dont even know how to Check to see if it's working or not... it looks like a relay I've seen near the battery though

The OVP relay is indeed in the little area behind the battery. It has its own 10 Amp fuse; check that first before spending big bucks on a new OVP. The tach and a number of other electronic things (ABS, EGR, etc.) run off of the OVP relay. If your system voltage goes too high, a Zener diode goes into conduction and blows the fuse, thus protecting the electronics downstream.

If the fuse is indeed blown, you can replace it and see if that fixes the problem, but don't forget to worry about WHY the fuse blew in the first place.

If the fuse is OK the the OVP itself may be bad. About $85? or am I thinking of something else?

Jeremy

jfikentscher · #5 03-03-2010, 07:45 AM

If the fuse is OK the the OVP itself may be bad. About $85? or am I thinking of something else?

The last OVP I bought was $96 plus tax at a dealership in Virginia while on a road trip.

benhogan · #6 03-03-2010, 07:56 AM

bingo but i would check all your fuses first though. one by one, take them out.

the only way to check if a relays is good is to put in a known good one. sorry, you'll have to buy a new ovp to really know.

on the plus side, if your old ovp is still good, you will at least have a good spare.

Aquaticedge · #7 03-03-2010, 03:01 PM

fuses are all new... only one that keeps popping is the passenger side power seat. I'll be pulling that seat soon to see if there's something up with the motor system on it