1990 300TE W124 - Continuous Hot air, Rough Idling, No Cruise Control and ABS light!

[Patrick_NZ]

1990 300TE W124 - Continuous Hot air, Rough Idling, No Cruise Control and ABS light!

I’m starting to accumulate a number of non-fatal issues with my right-hand-drive W124 wagon (212,000 kms) and need some help! I’ve recently had a water pump change and in the process of repairing the garage disconnected one of the AirCon hoses and discharged the system. After this ‘repair’ some things have started to go wrong…. The AirCon has not yet been regassed.

1. Firstly, ALL the vents now blow very hot air only, regardless of the dial settings. Obviously I don’t expect the aircon to work but I also don’t expect continuous hot air.

2. The battery discharged itself completely when the inside light was left on and now the ABS light comes on continuously. According to my Haynes manual, the ABS turns itself off when sensing low charge from the battery. I have now replaced the battery. The local Mercedes garage says the ABS should now automatically come on. It does not. They’ve also invited me down for an inspection and have suggested it may cost $1000’s to fix!

3. I’ve now noticed that the cruise control no longer works.

4. Also, that the auto-grab lock for the boot (trunk) rear door no longer comes on!

5. Not long after the water pump was replaced, the car started to idle roughly. I’ve changed the spark plugs to no avail.

Apart from never, ever using the repair garage again, I’m not really sure where to start. Not sure if any of these things are linked, but I love this car and want to return it to its former trouble free glory. Any and all help is gratefully appreciated.
Cheers
Patrick

[jhodg5ck]

Sounds like the OVP relay could be acting up...or could be voltage reg on the alt. Regs cost about 50-60$ here in the states...ovp around 100.

Jonathan

[Oldbeaver]

Originally Posted by Patrick_NZ

1990 300TE W124 - Continuous Hot air, Rough Idling, No Cruise Control and ABS light!

I’m starting to accumulate a number of non-fatal issues with my right-hand-drive W124 wagon (212,000 kms) and need some help! I’ve recently had a water pump change and in the process of repairing the garage disconnected one of the AirCon hoses and discharged the system. After this ‘repair’ some things have started to go wrong…. The AirCon has not yet been regassed.

1. Firstly, ALL the vents now blow very hot air only, regardless of the dial settings. Obviously I don’t expect the aircon to work but I also don’t expect continuous hot air.

2. The battery discharged itself completely when the inside light was left on and now the ABS light comes on continuously. According to my Haynes manual, the ABS turns itself off when sensing low charge from the battery. I have now replaced the battery. The local Mercedes garage says the ABS should now automatically come on. It does not. They’ve also invited me down for an inspection and have suggested it may cost $1000’s to fix!

3. I’ve now noticed that the cruise control no longer works.

4. Also, that the auto-grab lock for the boot (trunk) rear door no longer comes on!

5. Not long after the water pump was replaced, the car started to idle roughly. I’ve changed the spark plugs to no avail.

Apart from never, ever using the repair garage again, I’m not really sure where to start. Not sure if any of these things are linked, but I love this car and want to return it to its former trouble free glory. Any and all help is gratefully appreciated.
Cheers
Patrick

Once I had several strange and simultaneous failures in my MB 300E 1990, and it was a bad ground. The current tries to go through other ways and generates this.

There is a map of ground connections in the W124.

The repair garage is a danger!

Good luck with yr repairs.

OldBeaver

[smp]

ABS light could indicate the voltage regulator.
See here, kent talks about hard starts and the ABS light coming on occasionally:
Mercedes 190E Rough Start Problem Solved by Kent Bergsma - YouTube

If you haven't replaced it, it's a cheap part and may be due for a replacement either way.