ballast resistors
Safety Car
Joined: Feb 2006
Posts: 4,142
Likes: 703
Yes, they can go bad, they usually just quit working alltogether. With a fully charged battery you should have between 5 and 7 volts on the output side. I beleive the volt meter reading is prefered over the ohm meter reading, as the ohms can vary with the temperature of the resistor.
Race Director
Joined: Nov 2000
Posts: 10,338
Likes: 663
From: Beverly Hills (Pine Ridge) Florida
A typical ballast resistor failure (when the resistor "opens") is when trying to start an engine, and it fires, but then shuts off as soon as the key is moved to the "Run" position. In other words, the engine will run in the "Start" position (since the ballast resistor is being bypassed), but of coarse you are not going anywhere with the starter grinding away!
Plasticman
Team Owner
Joined: Oct 2000
Posts: 38,897
Likes: 1,920
From: Washington Michigan
The original "hot" resistor used from '56-63 was 0.3 ohms at room temperature, and the '64-'67 resistor was 1.8 ohms; the current reproduction runs from 1.8-2.2 ohms. As Plasticman said, they either work or they don't. 
