Join Date: Dec 2001
Location: Belleville, Illinois
Thanked 18 Times in 13 Posts
Re: What are symptoms of a bad starter relay?
The solenoid has two small posts, with a red wire on one and a light blue wire on the other, at least on my '78.
When you turn the switch to the start position there should be 12 volts on the blue wire. To bypass the entire electrical system you can run a jumper wire from the positive battery post to the terminal the blue wire is on.
There are many possible points of failure. The most common is probably a bad connection on one of the high-current cables, hot or ground. Also the solenoid case has to be grounded. If it's not, that will keep anything from happening, even if you jump to the blue terminal.
Solenoids are pretty reliable. When they fail it's usually the contacts inside. In that case it will click when you turn the key, but nothing more will happen.