Glow plugs control unit/relay pins - 2.9 OM602 engine
 

Hello! I need to change my glow plug control unit relay for my 5cyl, 2.9 OM602 engine. I already have one, but I'm not sure if I should try to connect it because of the different configuration of my smaller jack that goes on it - it has only 4 cables and the relay has 5 pins (50, 31, 15, LA, and a "T") - check attached image - I'm not sure what is the purpose of that connection in general, if somebody could explain, I would appreciate it :)

I saw on many online stores, that there are two types - one with 4 pins and one with 5 pins. But the distribution of the "main" 4 ones is the same (50, 31, 15, LA) - the other one has another pin with a "T" letter. I'm thinking that maybe I can connect the one I already have and leave out the 5th pin ("T") - anybody has any idea what is the T pin for? I was thinking that maybe someone around here knows if it would work to leave the 5th one out.

Thank you!

https://cimg2.ibsrv.net/gimg/www.mbw...e88d0eeb3f.jpg

http://w124-zone.com/downloads/MB%20...2w124intro.pdf

http://w124-zone.com/downloads/MB%20...03/15-0705.pdf

http://w124-zone.com/downloads/MB%20...03/15-4000.pdf

http://w124-zone.com/downloads/MB%20...03/15-4111.pdf

http://w124-zone.com/downloads/MB%20...am/ETM/ETM.pdf

http://www.superturbodiesel.com/std/...d.php?tid=1716

The last two seem the most helpful. T means temperature, seems to be coolant temperature.

Thank you so much! Yes, it seems the T is for the sensor for the coolant temperature. Mystery solved!

In the meantime, I did the proper thing and bought a new relay :) But I really like to understand what I'm doing on my lovely Bob (207D) :) For about three months all I'm doing is learning mechanics like in school and applying what I learned on the car.

Thanks again! I really appreciate it!