Trying to hook up a radio in a 74 F100 that never had one- I am trying to get power for the radio from the accessory point on the ignition switch. However, I can not get power there when the key is in the ON position or turned back to the accessory position. I can only get power there when I turn the key to actually start the truck. Is my ignition switch gone bad or am I missing something?? Please Help- Thanks

 

There's a 12v switched source at a 3-way female bullet connector (i believe it's yellow) just behind your headlight/wiper switches that you can tap into for accessories, it's generally empty right from the factory unless you have cruise control or intermittent wipers.

 

You're probably pulling power from the S post and not one of the A posts. However, you do not want to pull power directly from the ignition switch as it is unfused at this point; the switched signals from the switch first run to the fuse panel and then break out to the various loads. Always wire downstream of the fuse panel when possible.

But as MH said, there's an accessory tap on the left side of the dash; however you'd want to check if it's fused or not (I don't remember, unless maybe MH would know).

However, even if your truck didn't have a radio, your wiring harness should still have the 2-connector pigtail near the heater controls for one. It should have two wires; one is YELLOW with a BLACK stripe; the other is BLUE with a RED stripe. YELLOW with a BLACK stripe is switched 12 volts that's hot in ACC. or RUN. The only reason you wouldn't have it is if a previous owner cut it out, which is always a joy to deal with.

 

The accessory feed is not fused (at least on my '75 it's not).