My model is 1997 940 2.3 turbo with 210/211 alarm.
This tip means losing the alarm but who needs an alarm on a 15 year old (at least) Volvo (8-)#

I was unable to program a new Volvo sourced replacement fob and then lost my *only* original one. Apparently they are now incompatible, as they couldn't even manage using their re-programming device, so needs a new compatible alarm unit. Cost me £60 for their time!

I have connected a dual output remote ( HTX002/HRX002 - UNBRANDED - TRANSMITTER/RECEIVER SET-433MHZ | CPC ).
The receiver has two open collector outputs, each supporting 100ma GND sink. The Volvo lock control unit uses well under that - less than 20ma momentarily. Brilliantly, the Volvo unit (separate lock and unlock) requires GND shorts to actuate, so nothing else other than spade connectors is needed.

Do the following to connect the receiver unit, using plug spade connectors on the leads.

Remove and discard 210/211 alarm unit (behind glove box on mine).
Connect appropriate plug spade connectors to the receiver unit leads. ('lock' connector needs cutting narrower) and make one spade to spade lead.

Plug into the vacant 210/211 sockets as follows:

Spade to spade to 50E 50F to enable starter solenoid
Power - 30K (red)
GND - 31 (black)
Lock - AL2 (yellow/black - narrow connector. My 940 alarm schematic has white/black)
Unlock - ATR (Green/black)

 

my 1992 740 turbo wagon just has electric locks, activated by the drivers key, and I'd love to get around to installing a remote entry (sans alarm)... I've heard you can buy the drivers door lock 'motor' (really a solenoid), and it will just bolt in, then wire it with the other locks up to a relay activated by a remote system's reciever... presumably you would want to use a relay with seperate contacts for the drivers door and other existing door motors, so working the drivers key wouldn't power the drivers door.

not sure what my point in posting this was, but if anyone has any input on doing this, that might be useful to all of us.

 

I did that on my 1993 740. I fitted a motor with an extension arm that clamped onto the internal shaft of the lock/unlock push button. By reversing +12v and GND, one could operate the driver's door lock. That of course then operated the other doors automatically. Operation must be done with the door shut!

I did this with exactly the same CPC remote. I used five 12v relays to do the output. Two relays simply sent 5V and GND to the motor. Polarity was defined by two more double pole relays. One more relay was need to switch the polarity relays. All relays were activated direct by the ground sinks on the receiver unit (500ma max) and a permanent +12v connection the other side of the coil. The output relays *always* actuated. One polarity was just the two output relays. The other polarity needed the extra relay activated. Clear as mud probably (8-)# This is better: http://tfs.firshman.co.uk/temp/door-remote.jpg

The motor stalled until one released the remote button, but the motor was designed to handle that.
A 12V version of this would possibly do the job - MES Universal Central Locking: Wolf Elec Electronic Auto Accessories .

The receiver unit and relays were in the driver's well by the 'computer' control. Two output cables then went out to the motor via to the existing loom.

 

My wiring instructions above are incorrect.
There are errors on my original diagram. I had to think back twelve years!
New version: http://tfs.firshman.co.uk/temp/door-remote1.jpg

It is better to refer to the circuit diagram!

I reckon actually this design is now neater than my original. Isn't that always the way! I am thinking on the fly of course, so please point out any other errors (8-)#