Looking for info and or ideas. I have a 73 cs 2wd auto 390, recently got it up and running, when installing the motor went with the 3g upgrade, all has been great untill last weekend. Did a 90 mile round trip at night, almost home and dash lights adn running lights were blinking on and of in sync, at same time lights went of volt guage went to 12 then lights came back on guage went to 13.9ish, checked this after noon, with headlights off, no issue, turn on lights same thing running lights and dash lights blinking on and off, checked under the hood, one of the oem wires w/fusable link going to solenoid was very warm. Tomorrow will remove alt belt and she what happens, maybe the alternator is going south?
Thanks in advanced
Jeff

 

First, double check your connections/connectors.

Second, the headlight switch may be going south as it heats up.. that may explain the cycling which, in turn, may explain the warm fusible link.

 

The HD headlight harness, cheap, easy and highly recommended.

Truck Parts and Truck Accessories

 

good idea on hd kit, but need to source-find why it is wiggin out with the headlights on
thanks for the input, please keep it comming, will report back tomorrow after doing honeydo's

 

I ended up just stringing new wiring (have boxes of wire from sample harnesses from my old job) for the whole lighting system. new sockets, soldered all connections, and coated with liquid tape. the parking light/turn signals buckets are one piece with the wire pig tails though. PITA. luckily I had two extras from my parts truck. still the lights would work for 20 seconds and everything would shut off. found a wire on the light switch that had only 4 strands of copper left in it. PO just taped around it. everything works now.

 

1974 F100/350: There are two different types of parking lamps.

1973, 1974 before serial number T80,001: The park lamp lenses are separate from the steel park lamp bodies which have the socket/wiring swagged into them.

1974 from serial number T80,001, 1975/77: The park lamps are a one piece molded plastic assembly. The separate sockets twist into the lamps.
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1974 F100/350 Stylesides: There are two different types of taillamps.

1973, 1974 before serial number T80,001: The tail lamp lenses are separate from the steel tail lamp bodies which have the socket/wiring swagged into them.

1974 from serial number T80,001, 1975/79: The tail lamps are a one piece molded plastic assembly. The separate sockets twist into the lamps.

From serial number T80,001: Same tail lamps as 1975/91 Econoline & 1978/79 Bronco. These lamps have a foam rubber seal to prevent water from entering the interior, it peels off.

 

Cool. 'Glad ya found the problem.

One thing I do whenever I get a new-to-me vehicle is go on "hack patrol" and seek out so-called "repairs" of previous owners - duct tape, wire nuts, and connections that are simply twisted and wrapped with electrical tape gets excised and corrected with solder and heatshrink. The other stuff I have found include wood screws, drywall screws, sloppy silicone sealant, speaker wire used for electrical systems, and chewing gum.. yes, chewing gum.

 

Ok, got to work with it a bit today, removed alt wire from solenoid, ran truck with lights on, no wigging out, have 2 batt cables and 4 wires going to posative side of solenoid, used test light and connected one at a time, when connecting wire fro m three prong connector, part of 3g modification, had a very slight draw then light went off, three prong plug is also part of factory amp guage but 2 wires have been disconnected. reconnected everything, run truck, turn on headlights no wigging out of lights, now I have no turn signals, flashers do work, checked fuse under dash for turn signals it is good. Majorly confused now, any one have a wiring schematic for this area? any ideas?
Jeff