1977 Ford F-250 Electrical trouble

FARMERBUD

MEMBER
1977 FORD F-250
V8
4WD
MANUAL
70,000 MILES

My trusty ol' farm truck wouldn't start last Wednesday. I'd turn on the key and nothing happened. I wasn't too concerned as this has become a frequent occurrence in wet weather. I tried again the next day and it took right off. I drove it 1/2 mile and when I turned off the key the motor kept running. I pulled the 2 wire connector to the electronic ignition module to get the engine to stop. Thinking that the module was my problem, I took it to Advance Auto to get a replacement. They tested it and said it checked OK. On their advice, I bought a replacement switch. Installed it today and found the battery was dead when I tried to start. Charged the battery and when I reconnected the cables, the voltage regulator started buzzing. I pulled the cable off the battery and looked for a grounded wire. Didn't find any. Any suggestion as to my next move?

3 Replies

MHPAUTOS

MECHANIC
31,937 POSTS

You say that you replaced a switch. Was this a new ignition switch?

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Saturday, December 13th, 2014 AT 8:35 PM

FORD76460

MEMBER
14 POSTS

I had the same issue. I would turn on the headlights (so I knew there was power) as soon as I turned the key, nothing. Everything was dead. I'd tap on the starter relay and the lights would come back on. I traced the problem to the positive terminal cable and replaced that. It started right up after that. It could be just as simple as that.