I went and looked at a 1985 300sd today that had been parked for 2 years and we could not get the key to turn. I know that it is a pain to get the switch out with drilling or driving the pin out. My question is can I crank the car any other way to at least hear the motor run? Then I could decide if the car is worth persuing or not. The owner told me that it would be left up to me to get the car to run. Thanks in advance.

Pull the brown vacuum line off the shut off valve at the back of the IP. Jump 12 volts to the glow plug harness. Then, jump terminals 1 and 3 in the junction box on the right inner fender next to the alternator.

__________________
1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

How would I jump 12 volts to the glow plug relay ? Where to hook power to relay? Thanks

Take five strands of solid copper wire cut from romex, strip both ends of each. Stick one end of each into the glow plug harness after it's unplugged from the relay, twist the five other ends together and run a jumper wire from that twisted group of five over to the positive post on the battery.

__________________
1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

Thank you Kerry, thats what I love about this forum. I assume that when I short terminals together the car cranks and I release the shorted wires and the car will continue to run. Is that correct? If the car cranks and sounds good my next step will be to remove the ignition switch. I have a car that has this switch, so I think I could mabey just wire it temporarly and drive the car. Have you had to drill out the steering pin before? I have read that you can get to the locking pin by removing the instrument cluster, loosen the holding clamp, dropping steering wheel some and removing the complete switch. Am I on the right track? Again Thanks for the help.

Yes, release the shorted wires and it should continue to run. Yes, that's how you get the whole switch assembly out. You'll have to drill out the locking pin but it's easy to do since the metal is soft.

__________________
1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13