Dash board lights all lit up

[scottit]

Hello

All the dash board lights on my R129 500sl are lit up permanently. Has a

Mikenyone experienced this problem before and is there an easy cure? Any hidden fuses I should know about.

I am thinking maybe the battery is knackered?

The hard top wont release - is this related I wonder?

Mike
enquiries at lowercall.com

 

[television]

Welcome to the forum, how did all of these problems start

 

[scottit]

Not sure how the problems started - the car came to me in that way. I was wondering whether all the lights on the dashboard lighting up maybe something that happens if the battery is weak or suspect? I suspect this car had previously been standing for some time before it came into my possesion.

 

[television]

You are a little mean on the info side,does the car start, do you have to jump it, how does the engine run

 

[scottit]

Sorry....no meanest intended!
Car starts first time. Whilst driving it back from place of purchase, I put some petrol in and thereafter it seemed to run really badly as if it was not firing on all cylinders. Seems to have run OK ever since.

Occasionally the dash board lights do go out, leaving just the yellow ABS (?) light on and a red light on the left (sorry can't remember exactly which one)

The roll bar switch seems to operate the roll bar OK. Pushing the roof switch forward releases the back by a centimetre but nothing else seems to happen.

All other electrics seems to work fine despite the christmas tree dashboard.

Passenger window only goes down a third and then there is a clattering sound.....but I am assuming that is totally unrelated.

 

[television]

OK well first check the OVP relay, the one with the fuse on top. should be 12v on pin 87

 

[scottit]

Thansk for your speedy reply.

Actually I lied when I said that all the electrics worked. Just been down to the car to test the battery (which seems fine) and noticed that the headlights and rear lights do not work.

Excuse my ignorance in these matters. Is the OVP relay by the fuses in the front of the car? What do you mean by pin 87. Sorry to be a bit thick but if you tell me exactly where to put the black and red terminals of the voltmeter I will be forever indebted.

How do I use a voltmeter to test whether voltage is going to the 6 fuses in the back of the car?

Thanks

Mike

 

[television]

The over voltage relay location depends on the model of the car is it a 066,067 or 068 they are the numbers after the 129

 

[scottit]

Model number is 126 0672F097899

Hope that helps

Mike

 

[television]

In the boot in front of the battery do you have an orange relay with a fuse on top

 

[scottit]

Yes there is a green relay with a 30A fuse. The fuse looks fine.

I have taken the relay out and taken the green cover off. To test the voltage at pin 87, do I put the fuse back in with the cover off? Don't want to short anything out by touching the contacts....or indeed get a shock.

Does the engine or ignition need to be on when I test.

My friend who works across the road had a 500SL so I could maybe borrow some bits off his car if that helps the diagnostic tests?

Regards

Mike

 

[television]

Yes there is a green relay with a 30A fuse. The fuse looks fine.

I have taken the relay out and taken the green cover off. To test the voltage at pin 87, do I put the fuse back in with the cover off? Don't want to short anything out by touching the contacts....or indeed get a shock.

Does the engine or ignition need to be on when I test.

My friend who works across the road had a 500SL so I could maybe borrow some bits off his car if that helps the diagnostic tests?

Regards

Mike

you can get any shocks,the fuse must be in. All of these relays are the same if you can borrow one

 

[scottit]

Thought we had nailed it for a minute.

Took the relay out and put it back in. At first, the car wouldn't start - nothing when I turn the key. So, I locked it with electronic key, opened it, started the ignition the dash board lights all went out apart from the ABS. Went for a short drive and noticed:

MPG gauge never moved off Zero
Oil temperature guage never moved off zero
Fuel gauge seemed to be on zero (with £20 in tank)
Still no joy with roof

When I stopped the car at home and turned it on, all the dash lights were back on....albeit flashing intermittently.

Any further thoughts?

Mike

 

[television]

Thought we had nailed it for a minute.

Took the relay out and put it back in. At first, the car wouldn't start - nothing when I turn the key. So, I locked it with electronic key, opened it, started the ignition the dash board lights all went out apart from the ABS. Went for a short drive and noticed:

MPG gauge never moved off Zero
Oil temperature guage never moved off zero
Fuel gauge seemed to be on zero (with £20 in tank)
Still no joy with roof

When I stopped the car at home and turned it on, all the dash lights were back on....albeit flashing intermittently.

Any further thoughts?

Mike

Nothing will work without having the full 12v from the OVP relay,its the only thing common to all of the faults

 

[scottit]

Thank you so much for you help and your speedy responses - what a great forum! I shall replace the relay and let you know how I get on.

If you ever need any free help or advice with telephones or broadband, please do not hesitate to contact me personally.

Mike
MD LowerCall

 

[television]

On MBs on the ECUs pin 30 is always the input 12v you can check on all of the control units to see if they have 12v before you buy a relay,if you can borrow one so much the better

 

[scottit]

Good news and bad news.

I bought a new OVG relay from Eurocarparts for £15, plugged it in and all the dash boardlight NO LONGER LIGHT UP...that's the good news.

However....The red SRS light stays on for a minute then goes out after I drive for a bit. Not sure if that is normal.

None of the dash board instruments work - is there a simple fix for this?

Regards

Mike