Ignition switch resistance

[Fordfarmer]

What would typical - or acceptable - resistance be in an ignition switch?
Working on my Claas Dominator 106 combine on a Won't Crank issue. (Figured the post would get more views here than in the combine forum...and it isn't really a combine specific question) Has an on/off ignition switch and a push button start switch. Found a burned wire just behind the ignition switch. Maybe a bad crimp? Only looks bad right near the connector. Going to check for bare wire/shorts anyway. Back to the switch. It doesn't look like it was affected by the wire getting hot. The connector came off the tab on the switch - it hadn't gotten welded on by the heat. With a multimeter, I get no continuity with the switch off (as expected), and 0.7 ohms with the switch on. Acceptable, or is that going to make heat and increase the amp draw?
It's a diesel, so other than starting, I think the only power that might go through the switch is for the dash lights and gauges.

 

[T.R.K.]

Hold your meter leads together and subtract that number on the display from the 0.7 ohms you get through the switch.
It sounds like corrosion on the switch contacts. But What voltage do you have on the hot wire to the switch? And how much does it change on the wire leading to (I presume) the starter solenoid.

 

[MARK ROBKE]

When terminals do that, it is usually from a loose/bad connection/contact with each other. The terminal may be loose in the switch where it is riveted. Check that. If it is loose in the switch, I would just replace it. Mark.

 

[Russ from MN]

Squirt some WD-40 into the switch and turn it on and off a dozen time, do this twice, and then check resistance again, it might fix it. Working properly the switch should have about the same resistance as when touching the leads together.

 

[Tony in SD]

A better, more definitive test would be, to measure the voltage drop across the switch terminals and/or wire to switch terminal under load. They should all be very near zero.

 

[Fordfarmer]

What would typical - or acceptable - resistance be in an ignition switch?
Working on my Claas Dominator 106 combine on a Won't Crank issue. (Figured the post would get more views here than in the combine forum...and it isn't really a combine specific question) Has an on/off ignition switch and a push button start switch. Found a burned wire just behind the ignition switch. Maybe a bad crimp? Only looks bad right near the connector. Going to check for bare wire/shorts anyway. Back to the switch. It doesn't look like it was affected by the wire getting hot. The connector came off the tab on the switch - it hadn't gotten welded on by the heat. With a multimeter, I get no continuity with the switch off (as expected), and 0.7 ohms with the switch on. Acceptable, or is that going to make heat and increase the amp draw?
It's a diesel, so other than starting, I think the only power that might go through the switch is for the dash lights and gauges.

Thanks for the replies.
I have the switch out right now. I have the right style, but not the right size connectors to replace the burned one. I'll get the right size next time I go to town, and go from there.