Ignition switch or cylinder - no resistance

[g. faircloth]

82 300D - key turns freely and has no resistance at the end of turn in which it would normally have and then start? I've seen threads on key not turning etc but not on this problem. I imagine its the cylinder or switch, but which one? Is there an easy fix? Toggle Switch? (Screwdriver?) Thanks for your time and advice.

[Arthur Dalton]

http://catalog.peachparts.com/ShopByVehicle.epc?q=1982-Mercedes--benz-300d-Steering&yearid=1982%40%401982&makeid=63%40%40MERCEDES%2DBENZ%40%4063%40%40MERCEDES%2DBENZ%40%40X&modelid=6190%3AMBC%7C1504%3AED%7C10000135%40%40300D&catid=241580%40%40Steering&subcatid=241656@@Ignition+Switch&mode=PA

..or hard-wire a momentary/ON PB sw to the starter solinoid ..

[g. faircloth]

Thanks Arthur

The switch isn't as expensive as I thought but looks like a project to get to and replace? Any links for instructions on how to? Is it the cylinder or switch that is bad when the key turns freely? Thanks again.

[Arthur Dalton]

Could be either, but most likely the switch. The return spring should be built into the sw for positive starter deactivation positioning.............

http://www.peachparts.com/shopforum/diesel-discussion/142232-ignition-cylinder-tumbler-replacement%3B-mixed-diesel-gas.html#post1065596

[g. faircloth]

Thanks again Arthur for the reply

I see there's different body models or identifiers- 124, 126 etc. Which one is an 82 300D? I see instructions replacing the cylinder - will the switch come out with it or is that a different process. Since the problem could be either, might as well fix both.

[Arthur Dalton]

Those are Chassis ID..you have a 123 chassis.

et al..........

http://www.thebenzbin.com/chassisEngine.html

[g. faircloth]

Hello Arthur,

You mentioned yesterday wiring "ON PB" to silenoid. What is that and what does that entail? I'd turn key to to where glow plug light comes on - then use toggle switch wired to silenoid? Reading posts - there seems to be alot of frustration in replacing the switch, cylinder, housing, etc and $ could add up which neither one I'm interested in a 82MB when I could solve the problem for sure with a straight route to starter? Thanks for your time.

[Arthur Dalton]

" ON -PB " means a Momentary ON , Push Button switch.. which means the sw conducts when you hold down the button and does not when you release it .. [ momenatry ON].......you wire it between terminal #50 of the starter sol. and bat pos., thereby bypassing the ign sw. starter circuit .. that will allow you to crank the engine over at will...it simply replaces/by-passes the starter contact section in your ign sw and effects the starter circuit only. The Ign sw other circuits work as normal, so you still use the key, but the PB for crank.

[JimFreeh]

Might be the pot metal connector between the ign cylinder and the switch.

Jim

[g. faircloth]

Thanks Arthur - I truly appreciate your help.

Where is #50 terminal on silenoid? I recently replaced starter on Blazer and it had two wires - one larger than the other. PB sw found at? NAPA etc? Any size electrical wire requirements and/or install tips?