My air conditioning,signal lights,speedometer gas gauge and power window are not working while the engine is running but everything works if the battery is on only.

Asked by Nov 13, 2015 at 07:11 AM about the 2007 Mercedes-Benz C-Class C 230 Sport

Question type: Maintenance & Repair

9 Answers


I'm thinking that there is a problem with the ignition switch, cutting off the power supply to these accessories, as when you start you car, all power is diverted to the starter and ignition system, when releasing the key to the on position the circuit is interrupted.

But sometimes it works especially if the weather is hot

But sometimes it works especially when the weather is hot.


There may be a resistor somewhere for this circuit that may be going bad, not sure, still leaning toward the ignition switch...

The only thing that works is the radio when it does that.also I am smelling burn oil coming from front passenger side of the car.


Oil smell is oil burning off the motor or exhaust, probably a leaking valve cover gasket. Radio may be wired direct to a power source, can the radio play without the key on?

Yes it does so how can I check if there's a resistors going bad.

Or the ignition switch


These are things that need to be checked by a qualified persons, not necessary a certified mechanic, just someone who knows there way around a vehicle. The ignition switch is usually down toward the floor on the steering column and the resistor would be in the engine compartment if there is one, but I am not real familiar with Mercedes Benz, as they are not my forte'.

Your Answer


Looking for a Used C-Class in your area?

CarGurus has 25,566 nationwide C-Class listings starting at $2,100.


Mercedes-Benz C-Class Experts

  • #1
    Lorne Grandison
  • #2
  • #3
View All

Related Models For Sale

Used Mercedes-Benz E-Class
434 Great Deals out of 20,867 listings starting at $1,999
Used BMW 3 Series
951 Great Deals out of 33,308 listings starting at $1,300
Used Mercedes-Benz S-Class
114 Great Deals out of 7,245 listings starting at $1,200
Used Mercedes-Benz CLS-Class
53 Great Deals out of 2,164 listings starting at $5,999
Used BMW 5 Series
389 Great Deals out of 16,178 listings starting at $1,650
Used Audi A4
191 Great Deals out of 12,528 listings starting at $1,700
Used BMW M3
21 Great Deals out of 1,736 listings starting at $5,495
Used Mercedes-Benz CL-Class
21 Great Deals out of 511 listings starting at $4,000
Used Ford Mustang
317 Great Deals out of 38,894 listings starting at $1,995
Used Honda Accord
592 Great Deals out of 92,752 listings starting at $1,495
Used Mercedes-Benz M-Class
268 Great Deals out of 6,029 listings starting at $1,995
Used Dodge Charger
253 Great Deals out of 33,687 listings starting at $2,000

Used Cars For Sale

2017 Mercedes-Benz C-Class For Sale
136 Great Deals out of 2,705 listings starting at $23,991
2016 Mercedes-Benz C-Class For Sale
40 Great Deals out of 870 listings starting at $20,999
2015 Mercedes-Benz C-Class For Sale
175 Great Deals out of 3,911 listings starting at $14,890
2014 Mercedes-Benz C-Class For Sale
85 Great Deals out of 1,531 listings starting at $12,500
2013 Mercedes-Benz C-Class For Sale
52 Great Deals out of 1,318 listings starting at $10,962

Content submitted by Users is not endorsed by CarGurus, does not express the opinions of CarGurus, and should not be considered reviewed, screened, or approved by CarGurus. Please refer to CarGurus Terms of Use.