Parts Catalog Accessories Catalog How To Articles Tech Forums
Call Pelican Parts at 888-280-7799
Shopping Cart Cart | Project List | Order Status | Help

Go Back   PeachParts Mercedes-Benz Forum > Mercedes-Benz Tech Information and Support > Diesel Discussion

LinkBack Thread Tools Display Modes
Old 01-12-2001, 10:30 AM
Registered User
Join Date: Oct 2000
Location: Jacksonvill, FL, USA
Posts: 125
The glow plug light on the dash does not come on when I turn the key before I crank the starter. The bulb is good and the car starts fine (it has been 20 - 30 degrees F), so I think the relay is OK. The glow plugs have all been replaced within the last year.

Any suggestions?

Reply With Quote
Old 01-12-2001, 07:36 PM
Posts: n/a
Here is how to test the relay when the bulb does not light:

In the event of a problem, the lamp does not light despite car starting.

Pull 6-point coupler from preglow relay, turn key to position "2", bridge jack 1 and 2 of coupler.

If preglow indicator lamp is not lighting up, check bulb or replace. If the bulb is okay, then you need to check the blue/white wire that goes from jack 1 to the bulb for an interruption.

If the bulb is lighting up when you bridge "1" and "2", then you need to test the green wire going from jack "8" of the 8-point coupler to the the temperature sensor for interruption.

If that wire is okay also. Then you need to test the temperature sensor.
The resistance of the sensor should be:

At 0 deg Celsius: 8200 ohms
At +25 deg Celsius: 2440 ohms
At +80 deg Celsius: 290 Ohms

If you do not get similar readings, replace the temp. sensor. If every test is okay, then you have a bad relay.

This second test is for a light not lighting and the car NOT starting:

To test for problem when the glow plug light does not come on, and the engine cannot be started:

Pull 6-point coupler from relay, turn key into position "2"
test voltage of jack 2 against ground with a voltmeter

If no voltage(aprox. 12 volts)check the red and black wire going from the fuse to jack 2 for interruption

If you have voltage, connect voltmeter to jack 2 and jack 4 and test for voltage.

If no voltage,(aprox.12 volts), test brown line from jack 4 to ground for interruption.

If voltage is indicated, relay is defective.

Reply With Quote


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On

Similar Threads
Thread Thread Starter Forum Replies Last Post
1980 300sd... revray Diesel Discussion 1 11-12-2004 02:13 PM
1980 300sd not starting dieslpwr Diesel Discussion 11 10-06-2004 10:41 AM
300SD 1980 NEWLY PURCHASED w/PROBS mb300sd1980 Diesel Discussion 11 12-31-2003 12:47 PM
1980 300SD For Sale TClanton Mercedes-Benz Cars For Sale 13 12-24-2002 10:27 PM
Desperately Seeking a 300SD!! diesellady Diesel Discussion 14 08-28-2002 01:19 PM

All times are GMT -4. The time now is 05:03 PM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2021, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2018 Pelican Parts, LLC - Posts may be archived for display on the Peach Parts or Pelican Parts Website -    DMCA Registered Agent Contact Page