How to Troubleshoot a Mercedes


1. Check the electrical wiring and electrical harnesses on your 190E Mercedes Benz for exposed insulation or wiring. This is one of the more common problems with older 190Es and can temporarily be solved by wrapping the exposed wires in electrical tape or by using insulated heat shrink wrap, which can be applied with a heat gun. Be sure to disconnect the negative battery cable before handling exposed wires or circuitry.
2. Trace the positive battery cable to the starter on your 190E and tap the end of the starter with a hammer if you hear metallic grinding noises when you try to start your Benz. Alternatively, you may not hear any noises at all, except for a whirring and a click. Test to make sure that your battery is still good by turning on your headlights and interior lights before hitting the starter. The hammer trick will only work a few times with failing starter motors and can lead to permanent damage to the flywheel if done too many times.
3. Check for broken fuse links in each of the fuse boxes, especially if you are having start-up problems or idling issues. There are multiple fuse boxes and relay boxes located in the 190E Benz, one of which is typically located on the driver's console underneath the steering wheel. Many of the ignition related fuses are located in the fuse box next to the battery and the relay box is typically located on the opposite side of the engine from the battery.
4. Use an OBD (On-board diagnostics) translator for 190Es made previous to 1995 and an OBD II scanner for vehicles made in 1995 and later. The OBD II port is typically located within reach of the driver's seat and is more than likely behind a panel between the steering column and the door. Plug in the OBD II scanner and turn it on. Turn the 190E's ignition switch to the accessories position. The OBD II scanner will check for failing circuits or sensors that may be affecting your car's performance.