After messing with my non-working central locking system today, I got an idea.

Someone had cut the wires inder the dash which provide 12v and ground to the pump (my alarm buzzer is also missing). After a bit of fiddling, I got 12v and ground to the pump, only to find no signal from my door locks.

I'm assuming that the missing wires are also preventing 12v getting to the door switches.

Since I want to do a keyless entry, I got to thinking, why not just set up a system in the trunk with two relays to provide either the 12v or the grounded circuit between the pump power and the three-pronged switch on the pump.

The double pronged connector is always hot. The three pronged connector has either 12v at all three connections (Two front door switches and trunk switch) or Ground at all three, depending on whether the key switch is in unlock or lock position.

I reckon a remote/relay setup in the trunk will work, and won't give a rat's butt whether the key switches are working or not.

As long as my system holds vacuum (which my Mityvac show it does), this should work, yes?

Or am I being a nebbish again?

Any and all electrical types please comment on this.

TIA

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1998 E300 +310,000K
1996 E300 +460,000K

If you check the archives, that's usually how it's done. Crutchfield used to sell a relay harness to simplify the wiring.

Sixto
93 300SD

You can install an electric actuator to pull/push the door lock mechanism on the drivers door. I use it on mine and it works fine. It will work with any alarm that has a remote lock feature or they can be bought as a self contained remote lock kit..

is there a recommended brand/model of electric actuator?

thanks.

__________________
1982 300TD 210K miles ("The Replacement" aka "The Anvil") - SOLD
1979 300SD 245K miles (never ending project)
2007 Pinarello F3:13
1995 Ducati 916 (SOLD, sniff)
1999 Ducati 900SSie (SOLD)

i found these on german ebay and bought a set. i had it sent to my aunt there and she will send it to me. i payed $25, plus shipping, and it looks just what you had in that previous picture. i will post my findings.

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Grey '91 350SDL 214k Dad's car
Beige '81 240D 4 Speed 254k SOLD
Blue '82 300D 225k SOLD
White '95 E300D 46k SOLD
Blue '87 190D 2.5 Turbo 315k SOLD
Brown '80 240D 4 Speed 716k SOLD
Beige '80 300D N/A 119k SOLD
Blue '85 300D Model 186k T-Boned

Pretty much anything.

If your city has a CarToys store, they sell them for about $15 each.

Not much left here , but the PepBoys just up the road finally opened up again. Worst case I see there's some available online.

thanks for the tip

__________________
1982 300TD 210K miles ("The Replacement" aka "The Anvil") - SOLD
1979 300SD 245K miles (never ending project)
2007 Pinarello F3:13
1995 Ducati 916 (SOLD, sniff)
1999 Ducati 900SSie (SOLD)

There's tons of actuators available on eBay.

What I'm proposing is a system that doesn't need actuators. Rather it works directly with the pump.

I wonder if Crutchfield still has the harness? I need to get in touch with them about my stereo so I'll ask.

I'll check the archives and see what comes up.

__________________
1998 E300 +310,000K
1996 E300 +460,000K

Ahh, there was a lot of stuff about that. Hadn't come up in my previous general searches about inoperative central locking system.

I'll test the system with my handy jumpers to make sure everything's operable (junk yard locking pump), then order a remote and relay.

I'll post back with the results.


Thanks.

__________________
1998 E300 +310,000K
1996 E300 +460,000K

On my 1984 300SD, the circuit board inside the pump housing was bad. I bought a passenger side door lock element to put in the driver's side and connected a vacuum line to it.

Using the diagram below, I wired in a keyless entry system directly to the pump motor. On my car, the luck creates a vaccum to lock and generates pressure to unlock; the motor runs in either direction to control the pump.

http://24.14.137.240:8080/saab/Relay_Plan_DAD.jpg

Thanks.

__________________
1998 E300 +310,000K
1996 E300 +460,000K

Crap. Pump I ordered off eBay is no good. Seller seemed very cool, so I doubt it'll be a problem.

Oh well, the search continues...

__________________
1998 E300 +310,000K
1996 E300 +460,000K

I just bought a kit off ebay...I'd been wanting to do that for a long time. Its a kit with the little computer box, two remotes, and two motorized actuators. (and a bunch of wiring) $35 not bad. I'll install it as soon as I get it. Now I won't have to worry about my lock freezing shut this winter, I won't need the key!

__________________
-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)

If my door switches were working, that's exactly how I'd do it. Unfortunatley they're not, so I'm going the direct-to-pump route.

Turns out my pump is bad at the circuit board -- the motor/pump work prefectly. Last night I pirated it and soldered two relays (lock and unlock) and bench tested it. So far, so good. Cool thing about that is all my new relays/wiring will fit nicely along with the pump in the old housing.

The remote I got from AutoZone only provides short 300ma pulses for the lock and unlock functions. I think I may need a timer relay to provide more time for the pump to do it's job.

That'll be clear once I mount the unit on the car.

__________________
1998 E300 +310,000K
1996 E300 +460,000K

300ma or 300milliseconds? 300ma is not enough juice to run the pump an 300milliseconds in not long enough to unlock all the actuators. On my 300Sd it took 2-3 seconds to lock/unlock all the elements.

The kit I bought from AZ had a dip switch to select 300ms or 3 seconds. You may want to check yours to see if there is a similar setting.

The wiring diagram above will help with the 300ma problem.