Glow Plug Relay OM601 Question - PeachParts Mercedes-Benz Forum

mouramen · #1 08-31-2008, 11:39 AM

Hi guys,

My Glow Plug light has been acting very strange, sometimes it turns off and sometimes doesn't!
I checked all plugs and all measured 0,5 Ohm, I disassembled the relay and the contacts were all black and with oxidation, cleaned everything up but noticed that one of the contacts is a litle bent? is this normal? It does look like factory bent...

Diesel911 · #2 08-31-2008, 12:11 PM

I have never had my GP Relay apart to know for sure concerning the bent arm. But I would like to know if it is working now?
I have cleaned contacts on other regulators and solenoids before and found that you can buy some time this way but ounce the contacts are burned the adjustment of the regulator is off due to the burned out area.

In the old days the gap between regulator contact points was sometimes adjusted by bending the regulator arm but the bend in the arm could also be due to heat as burned contacts have create more resistance than good ones.

Jeremy5848 · #3 08-31-2008, 12:23 PM

Diesel911 is correct. The bent contact is due to overheating -- the color of the metal alone says that. As the contacts get burned, they become "ohmic contacts;" the voltage drop across the contact times the current through the contact equals the power dissipated in the contact. That power shows up as heat.

It is possible to repair and clean the contacts but you are probably on borrowed time with that relay. Sometimes relay contacts have special surface shape and/or composition that you alter/remove when you clean them. The repaired/cleaned contacts will burn more quickly the second time. Nonetheless, it's worth making the effort -- you might get many more glow cycles out of such a relay.

Jeremy

mouramen · #4 08-31-2008, 01:00 PM

The 2 contacts that you see on the pic are doing the same function, even if one is making bad contact the other does the work for it!

I polished the contacts and cleaned every thing up, I tried the glow cycle 30 times and each time the light went off in 4-5 secs, I guess it's working perfectly, lets see for how long...