Breakdown Information
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For everyone with a Dodge gasoline, especially older models:
Carry a spare ballast resistor. Most are rectangular white ceramic, roughly 1" wide and 4" to 5" long, with two electrical connectors and a single mounting screw. Unlike voltage regulators and starter relays, ballast resistors are not grounded and may be mounted on nonconducting material such as plastic.
The ballast resistor reduces voltage to the coil, thereby increasing sparkplug life. The starting circuit bypasses the ballast resistor, resulting in a hotter spark when starting.
Symptoms of a bad ballast resistor: Your vehicle fires while you hold the key in the start position (because of the bypass) and dies as soon as you let go of the key (because in the run position, current is supplied to the coil through the ballast resistor).
I haven't bought one in a while but I seem to recall that my spares were less than $20.
As an emergency fix, you can connect the two electrical leads together but doing so will shorten the life of your sparkplugs and other ignition components.
I first encountered this problem on my '77 Dodge B200 van, purchased new and well maintained. My 1970 Explorer motorhome, on a 1969 Dodge M300 chassis, also has a ballast resistor but hasn't needed a new one yet.
The bad ballast resistor kept my van from going anywhere and frustrated me because I couldn't figure out what was wrong. (I'm a fairly good mechanic with extensive knowledge of the electrical systems in older vehicles - I can draw most of the typical wiring diagrams from memory.) A friend suggested I check the ballast resistor, saving me the expense of a tow. (I bought him a case of his favorite beer in thanks.)
I've heard of enough similar experiences from other people to convince me to always carry a spare. I haven't heard of any going out while the vehicle is moving although I imagine it's possible. All of the cases I've heard of showed up while trying to start the vehicle, leading me to believe a current spike during shutdown or starting cause the ballast resistor to fail.
Hope this helps someone.
Carry a spare ballast resistor. Most are rectangular white ceramic, roughly 1" wide and 4" to 5" long, with two electrical connectors and a single mounting screw. Unlike voltage regulators and starter relays, ballast resistors are not grounded and may be mounted on nonconducting material such as plastic.
The ballast resistor reduces voltage to the coil, thereby increasing sparkplug life. The starting circuit bypasses the ballast resistor, resulting in a hotter spark when starting.
Symptoms of a bad ballast resistor: Your vehicle fires while you hold the key in the start position (because of the bypass) and dies as soon as you let go of the key (because in the run position, current is supplied to the coil through the ballast resistor).
I haven't bought one in a while but I seem to recall that my spares were less than $20.
As an emergency fix, you can connect the two electrical leads together but doing so will shorten the life of your sparkplugs and other ignition components.
I first encountered this problem on my '77 Dodge B200 van, purchased new and well maintained. My 1970 Explorer motorhome, on a 1969 Dodge M300 chassis, also has a ballast resistor but hasn't needed a new one yet.
The bad ballast resistor kept my van from going anywhere and frustrated me because I couldn't figure out what was wrong. (I'm a fairly good mechanic with extensive knowledge of the electrical systems in older vehicles - I can draw most of the typical wiring diagrams from memory.) A friend suggested I check the ballast resistor, saving me the expense of a tow. (I bought him a case of his favorite beer in thanks.)
I've heard of enough similar experiences from other people to convince me to always carry a spare. I haven't heard of any going out while the vehicle is moving although I imagine it's possible. All of the cases I've heard of showed up while trying to start the vehicle, leading me to believe a current spike during shutdown or starting cause the ballast resistor to fail.
Hope this helps someone.
