Q: I Reversed battery cables on My 1992 Mercedes SL500. Now it turns over but won't start

asked by on December 26, 2016

I hooked up battery cables backwards and blew something car turns over but won't start replaced OVP fuse 20amps still won't start

My car has 10000 miles.
My car has an automatic transmission.

Car is not starting Inspection $79.99 - $89.99 Get a Quote

When the battery cables are reversed, It only takes an instant to do a lot of damage. The Alternator and the ignition modules are probably toast, And any or all of the ECU’s are probably damaged. The good news, if you can imagine any in this situation, is that this car was built before Mercedes started "marrying" control modules. That means you can do substitutions with a salvage car.if you can find one. Later Mercedes modules were matched to each other with a code so that chop shops could not get away with selling used modules but your car was built before this happened. Sorting this car out will take a technician skilled in electronics equipped with a lab scope. If you want to get some professional help with this, you can contact Your Mechanic to have a technician come out to your home or office to check out your car and give you an evaluation.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

What others are asking

Spilled water on shifter

Hello. Spilling water on the shifter could have affected a lot of different things in your car. There are sensors, wires, and connectors under your shifter. It is possible that water could have damaged some or all of these things....

Immobiliser light flashing engine system failure and engine not starting.

Check the engine management control fuse (3amp) in the fuse box next to the battery. this fuse is only 3 amp and can easily burn out giving the symptoms you have. Also check the fuses in the fuse box below...

Car wont turn over clutch ism clicking

I would recommend checking your alternator as well as all fuses. Test the alternator with a multi meter to ensure that it is maintaining 13.8 - 14.2 volts while the vehicle is running. Next, use a circuit tester to test...

Camshaft Sensor Replacement

Hello, thank you for writing in. When looking at the engine you will see the two different banks of the engine. These are the heads, and inside the heads you find the camshafts. To track the camshaft's location for timing...

It takes two or three tries to start the car.

Hi, thanks for writing in. I recommend testing the fuel pressure and monitoring the pressure after the key is turned off to see if the pressure drops to zero. If it does, then the system will need to be tested...

Airmatic system not rising

Issues with this system are not common. The system has a set of bags that get filled with air to level the car when the sensors determine it is riding low. If the pump fails or the bags themselves develop...

my immobilizer is broken, my car wont start.

You would need to have the immobilizer replaced and reprogrammed by a Honda dealer. This is the only way as it cannot be bypassed. You mentioned you had a few mechanics look at the car already, but if you'd like...

My car starts, runs, and goes into gear but it won't move.

Hi there. Check the torque converter bolts and make sure that they are installed into the flex plate. The sound is the torque converter hitting the sides of the bell housing. It also could be the flex plate being broke...

I have 1997 isuzu kb200 carburetter type, washed the engine and the car can not start

Hello. If your vehicle will not start after you washed the engine bay then it may be possible that something may have gotten wet. The first thing I would do is check to see that there is no moisture in...

Related articles

Mercedes-Benz Certified Pre-Owned (CPO) Car Program
Shopping Shopping for a used Mercedes-Benz vehicle often leads many drivers to consider certified pre-owned options. Mercedes-Benz is one of many manufacturers that have a certified pre-owned (CPO) program. Each car manufacturer structures their CPO program differently; read on to...
A Buyer’s Guide to the 2012 Mercedes-Benz R-Class
This This non-minivan, non-SUV, non-station wagon is nothing if not a class unto itself. Mercedes classifies it as a crossover but it reps more like a combination of all of the above. Its precise identity is really immaterial however, as...
A Buyer’s Guide to the 2012 Mercedes-Benz SLK
It’s It’s not a sedan and it’s not quite a sports car, but chances are that brand-loyal fans desiring that luxury-class hard-top convertible with some oomph under the hood won’t care. The SLK roadster boasts three attractive engine options, and...