BenzWorld Junior Member
Date registered: Jan 2009
Vehicle: ML320 1999
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Dash lights, coolant sensor and trouble starting
OK, finally sorted out all my issues. Here are my problems and solutions:-
1. Dash lights out on exterior temp display and time. Got 5 replacement bulbs from Mercedes for Â£12.00 (got a few spares as my ML is 10 years old and so will be needed soon I think). There are 2 large ones and 29 small ones, it was the small ones I needed and managed to get the instrument cluster out OK, albeit a bit fiddly, but done it easy enough. The bulbs are dead simple to fit as they come in their own holders and even a car novice like me did it no problem.
2. Coolant gauge not working. I thought this was related to the dash lights n/w and had nightmares about needing a new instrument cluster (as Mourtadas suggested, $1200!!) but just a coincidence. Checked the coolant sensor connection on the engine, found it to be not quite home, pushed it in til I heard a click and it worked OK immediately. After talking to Merecedes and much searching in the forums I found where the sensor is, I searched under coolant sensor but eventually found it under cooland sensor! It is a black oval sensor with 2 wires, one is green with a red stripe, the other is brown with a white stripe (thanks to 43sqd and Mercedes Benz World, Surrey).
3. Trouble starting. After switching the engine off and trying to start again, it wouldn't start for about 5 - 10 minutes and a strong fuel smell. First I suspected the crank position sensor after reading much about this on the forums, but having spoken to Mercedes about the problem with the coolant sensor they suggested that if the coolant temperature wasn't being picked up, the engine would presume that every start was from cold and would supply max fuel. When the engine was hot it would cause the engine to flood and then a 5 to 10 minute period was needed to let the fuel evaporate and the engine cool down a bit. As soon as the coolant sensor was fixed I could start the engine straight away form cold or hot. One thing to note was that the Mercedes service tech said that if the CPS is defective, there would almost definitely be an engine warning light up on the dash. Also, he did tell me to have a go at changing it myself first as it is quite an easy part to replace. All the more reason to feel good about owning a MB.
Having had joy when I bought the car, to concern when things stopped working, I am now back to joy again with a bit more confidence in my own abilities than before thanks to this website. Unless it's a catastrophic failure I shall be back again one day for more DIY repair. Thanks for your help oreif.