Electronics Advice Needed!

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Iceviolet

Active Member
Joined
Mar 26, 2014
Messages
192
Location
West Yorkshire
Car
2007 CLS 500, W114 280CE (resto)
Hi,
I have been having issues with my power boot opener/closer on my CLS 500. Everything appears fine on STAR, boot normalised, no faults recorded. I did some investigation and I have I believe that the problem lies within the control unit. In particular the motor control relay. I have come to this conclusion because I put a voltmeter across the outputs from the control unit that go to the motor, and when I operate the close or open I get a 12v flicker on the meter for a split second. I would be expecting the voltage to stay on until the motor operates and boot lid moves into position.
So instead of spending what is likely to be £200 plus on a new control unit I am wanting to replace the motor control relay.
Not so simple, as the relay in question is obsolete and I am no electronics expert, so I need some advice on a suitable replacement??
The relay is a NEC EQ1-31000S, See picture below.
I have found a relay on RS ( JSM1125 | Panasonic SPDT PCB Mount Automotive Relay, 12V dc Coil, 15 A | Panasonic ) which is very similar apart from the max current, 15A instead of 30A on the original. Would this be suitable?
Thanks,
Sam
 
afraid i cant help with the component, you might find the higher current draw might pop the new one.

i had a problem with my control unit where it would almost take your head off, i ended up sourcing a 2nd hand one on ebay which done the trick.
 
OK, can I suggest you put a voltmeter across the relay coil ? It could be the ECU is only briefly turning on the relay because some other sensor is not sending it back something it expected !

Richard
 
I may end up replacing the control unit but I would like to try and find the fix if I can.

Grober, yes that one has the wrong pin layout and Badvgood I think that one would definitely need to wired externally. I will keep looking, there must be a replacement somewhere.

Richard, I don't know how I could get the voltmeter across the coil without removing from the car, so that would not work. I might remove the relay from the board and try and test it some how??
 
you should also check that the motor, driven by the relay, has not gone short circuit. If it has the symptoms would be similar - the circuit would (hopefully) go into current shutdown to protect everything else.
 

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