1998 S70 Door Lock Actuator Issue?

ferocity02 · Post by **ferocity02** » 18 Oct 2015, 18:41

1998 Volvo S70 GLT with 186000 miles.

Even since I bought the car the driver's door lock hasn't worked quite right. It will unlock just fine with the key or when pulling up on the plastic mast thing. But it will never unlock when using the unlock buttons inside the car or with the key fob. The other doors work fine.

When using the button you can hear the actuator doing something, and the mast moves ever so slightly, but it will not unlock. Is this a bad door lock actuator (the electric part)? Or something else? Thanks!

Post by **bmdubya1198** » 18 Oct 2015, 20:05

This might help:
My rear left door is having that problem. It unlocks when I pull up the pin, but it won't always unlock with the remote.

Post by **JRL** » 18 Oct 2015, 21:29

It's broken, common

Post by **cn90** » 19 Oct 2015, 08:00

Search the internet for "Mabuchi" motor, about $5 on ebay etc.

New Lock Actuator is about $125 or so at dealer.

Best option is to operate the door manually, it costs nothing.

Post by **BEJinFbk** » 19 Oct 2015, 08:15

There's a kind of a "circuit breaker" in the door lock motor.
It's a little wafer that's designed to protect the motor if power
is sent to it for too long. Quite often, it fails in warmer weather.
The motor can be disassembled and the part can be repaired
or bypassed completely. There are some posts here if you do
a little searching.

Post by **cn90** » 19 Oct 2015, 08:41

If you look at the video below, the fellow shows you how to disassemble the Mabuchi motor and clean it.
Since the Mabuchi motor is only $5 brand-new on ebay, I'd go for a new Mabuchi:

During re-assembly, use some RTV or sealant, gently clamp it as shown in the video, let it sit for a few hours before putting it back in the car.

Post by **scot850** » 19 Oct 2015, 12:10

The shaft has the worm drive on it. Do the new motors come with this or can you somehow transfer the drive over to a generic motor? If the drive can't be swapped over, is there a specific part number to buy of Mabuchi motor?

This looks a lot like the motor in the headlight wipers, although the thermal resistor is external for that version.

Neil.

Post by **cn90** » 19 Oct 2015, 12:27

The worm drive can be transferred but the operation is very delicate.
Buy the motor that already has the worm drive is on ebay, buy it and done with, don't mess around with worm drive transfer.

Post by **cn90** » 19 Oct 2015, 12:32

If you want to remove the worm gear, see the link below: basically heat gun and a little tap with hammer:

http://www.northamericanmotoring.com/fo ... ement.html

ferocity02 · Post by **ferocity02** » 20 Oct 2015, 09:17

Thank you for the replies everyone!

I forgot to add one key piece of information. The door will LOCK just fine with the key AND buttons. But it will not UNLOCK with the buttons. It will only unlock with the key.

Does this change what could be wrong?