I have a bad ignition switch, I can turn the key and I get power to the radio and dash lights but the car won't turn over. The car has a brand new battery and starter. I'm pretty sure it's the switch because I can't hear the glow plug relay kicking off either. Is there a way to bypass the switch and get this thing going?? Thanks in advance

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1981 240d (The Diplomat Car), 1988 Dodge W250 (The Bruiser), Volvo 262 (The Never Ending Project), 1972 Duece and a Half (Will Winch Over Anything)

Using a Jumper Wire or Remote Starter Switch on Terminals 1 to terminal 2 will crank the Starter and start the Engine.

If that does not work then you have an issue with the Starter or the Wiring/Ground Cable.

If you have a automatic transmission it could be the Neutral Safety Switch.

If you need a free Tow get on the Internet or call one of the Auto Clubs and find out if you Join right now if you can get the free Tow right after you Join.

Disconect the Brown Vacuum Hose (With Blue Stripe?) from the Shutoff Valve on the Fuel Injection Pump and plug off the Vacuum Hose and see if that allows you to start. If so the Vacuum Switch on the Steering Colum could be no good.

Jumper wiring the starter to crank it and start the Engine does not mean that the Charging System is going to work.

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84 300D, 82 Volvo 244Gl Diesel

Try to start the car in neutral.

Possibly NSS and a fuse blown (glow plug relay does work independently of NSS doesn't it?)

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1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!

The OP mentions that the car won't turn over so I agree with the most likely being the NSS. On mine, with worn/missing shifter bushings, I have to play with the gear selector to get the car to start.

(The GP relay has a NSS input but the diagram makes it appear that it may be with regards to the temp sensor. Hmmm....I wonder if cold start problems might have something to do with the NSS? Just a thought.)

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Sam

84 300SD 350K+ miles ( Blue Belle )

Ditto, try in "N" and wiggle around there. If your plastic shifter bushings fell out (common), giving slop in the linkage, the tranny usually doesn't get into "P" when the shifter is there. If so, the NSS is doing its job fine. You can actuate the starter easier a bit upstream from where post #2 shows. In my 84 & 85, use the terminal block next to the battery, where those same wires are routed. The thick one is "always +12 V" to the starter. The thinner one going down in the same sheath is the "contactor actuate" wire. Jumper the thick to thin and the starter should actuate (as I recall), even if the tranny is not in "P", so set the parking brake (always, everywhere).

I don't know a simple way to supply 12 V to all 4 glow-plugs, since each has a separate wire from the relay box. You would have to jumper each separately. Heating up 2 glow plugs should get you going.

A bad "ignition" switch is likely. I recently traced my "no cabin blower" problem to my ignition switch. I don't get the 12 V feed reliably, and it drops to 7 V by just plugging in the climate button box.

Remove the vac line from the shutoff pod. There is a plastic box with leads going to the battery up on the passenger fender. Jump those two together and she should start up.

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$60 OM617 Blank Exhaust Flanges
$110 OM606 Blank Exhaust Flanges
No merc at the moment

Thanks for all the input guys. I had to remove to vac line from the shutoff pod and then I was able to jump the starter like you suggested. I've checked all my connections, grounds, etc. I think it's time for a new ignition switch. Again, I really appreciate the help, without you guys I would have been in for a tow...

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1981 240d (The Diplomat Car), 1988 Dodge W250 (The Bruiser), Volvo 262 (The Never Ending Project), 1972 Duece and a Half (Will Winch Over Anything)

So just to make sure before I order one. The ignition key turns freely, it just doesn't start the car. Will a new ignition tumbler fix this problem or do I need to do more trouble shooting?

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1981 240d (The Diplomat Car), 1988 Dodge W250 (The Bruiser), Volvo 262 (The Never Ending Project), 1972 Duece and a Half (Will Winch Over Anything)

The tumbler is not the same as the switch. It likely has nothing to do with the problem if the key can be turned to the start position without issue. NSS, ignition switch or starter relay are the usual culprits.

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1991 F250 super-cab 7.3 IDI. (rebuilt by me) Banks Sidewinder turbo, hydroboost brakes, new IP and injectors.
2003 S430 - 107K
1983 300SD - Tanoshii - mostly restored ~400K+.
1983 300SD - Good interior. Engine finally tamed ~250K.
Monark Nozzle Install Video - http://tinyurl.com/ptd2tge

There is no starter relay in a W123. You should take a look at a wiring diagram so you know where and what to test. I would suggest using a test light starting at the starter solenoid, working back to the NSS then the ign electrical switch.

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85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

Right, I guess I meant starter solenoid.

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1991 F250 super-cab 7.3 IDI. (rebuilt by me) Banks Sidewinder turbo, hydroboost brakes, new IP and injectors.
2003 S430 - 107K
1983 300SD - Tanoshii - mostly restored ~400K+.
1983 300SD - Good interior. Engine finally tamed ~250K.
Monark Nozzle Install Video - http://tinyurl.com/ptd2tge

If it does end up being the ignition switch, you want to order the entire assembly, tumbler and housing pre assembled as one unit. Ask me how I know this.