Central Locking issues - looking for some guidance

[jayjpl]

Hi Everyone, apologies for beating the dead horse on this topic.

I just got a 1991 318i sedan, and central locking is not working whatsoever. Reason im trying to chase this down is because im trying to get keyless entry or just lock all doors as a whole, was hoping to get this one here: https://rclick.co.uk/shop/index.php?...roller=product

When i got the car, i could only lock:

- Passenger front - from inside and out
- passenger rear - from inside
- drivers front - from inside only
- trunk - outside only, doesn't touch the other locks at all.

Could not lock:
- drivers front: from outside
- drivers rear: deadlocked open, doesn't move whatsoever.

I opened up the CLCU by the drivers footwell, and soldered it together. Unfortunately it just made things worse and now all doors are deadlocked open, I can only lock my rear passengers door.
before i put everything back, I investigated the CLCU and checked, it looks like its burning the solder again and something in the circuit is failing. Before the solder burned up again, i heard the CLCU activate and try to activate but nothing happens.

Some notes:
- Rear drivers window does NOT roll down whatsoever. I swapped switches and its illuminated. so i doubt the switch is the issue.
- Checked the plug that goes into the A-Pillar, very clean, no corrosion whatsoever
- did not do the red/black wire mod because I've heard stories of it causing issues.

I'm at a loss, looking for guidance. I'm a serial e46 owner, so i've never had to deal with stuff like this hahah.

Would it be safe to say its the rear drivers actuator creating issues? Any ideas on how to track this down?

Is it also safe to assume that Central locking NEEDS to work if I want to get keyless entry?

Thanks in advance folks.

[reelizmpro]

Sounds like you have a troubleshooting nightmare ahead of you. If the central locking doesn't work, the driver's doors should still lock mechanically with a key. Try another CLU first and observe any changes and go from there. Unlocking/locking from the trunk should control all the other locks. If some work and some don't then you know you have a contact issue or bad actuator issue. If it doesn't work at all then suspect the CLU or signal to the CLU. Yes, central locking needs to work if you get a Keyless system. Unless of course you add your own relays to control the locks.

[ghrays]

The Electrical Troubleshooting Manual for your car’s year and model should contain several pages of central locking troubleshooting presented in a logical order. For example, the first test is of fuse 27 by checking the interior light delay function.

On a 1990 325i, these are found on pages 5126A-0 through 5126A-3, and follow the electrical diagrams for central locking on pages 5126-0 and 5126-1.

I recommend you obtain a copy of your ETM (scanned copies are available free online) and use a multimeter to find, and ultimately cure, your electrical/ mechanical faults.

it’s curious, when I looked at the 1991 318i ETM, central locking is not listed and on page 6330-0, interior light timer control, the power (Rd/Bk) wire going from pin 3 of the interior light timer control unit to pin 3 of the CLCU is listed as “not used”. Obviously if your car has a CLCU it has central locking.