Bad check engine light?
Thread Starter
Member
Joined: Jan 2006
Posts: 178
Likes: 4
From: Austin, TX
2012 C250
Bad check engine light?
I have a question about my check engine lamp. Anyone know what could cause it not to function? I've already ruled out a bad bulb (a new bulb from the dealership does not light up in the same socket, nor does a known working bulb from another part of the instrument cluster). The MIL circuit works according to OBD readers, and codes get stored when appropriate, but the check engine lamp just doesn't work. The last time I attempted to tackle this issue, I put a voltmeter on the leads where the bulb connects and did not get 12 volts, whereas I did on other bulbs. Does anyone have any suggestions as to where I should go from here? I *really* don't want to pay $1200 for a new cluster from the dealer, but technically I can't pass inspection if that lamp does not turn on. Generally in the past I've been lucky in that the inspector tends not to notice that the CEL lamp just doesn't work, but I don't want to base my inspection every year on a maybe.
Anyone have any suggestions?
Anyone have any suggestions?
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Joined: Apr 2007
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300E a couple 1994 w124wagon E320 Wagon/,1971MGB Track/Rally, MG Midget Autocross ,2000 E320 wagon.
The cel should
light up for a few seconds at start up to show it is functioning properly.With the cluster pulled put the multimeter to it at start up and see if it has life.Otherwise one of the cel fuses or relay in the ecu box or the wire is shot due to a rodent eating the insulation.
Have you intentionally triggered a cel code and read it on the obd2 hh scanner?
Have you intentionally triggered a cel code and read it on the obd2 hh scanner?
Thread Starter
Member
Joined: Jan 2006
Posts: 178
Likes: 4
From: Austin, TX
2012 C250
I haven't intentionally triggered the CEL, but I've had plenty of stored codes over the years that never kicked it on. It also does not turn on when putting the key to the on position (right before starting the car). Fuses are all good. How should I test the relay, and where should I look for a relevant wire to check for damage?
