Ignition Control Module AKA brain box. A must have glove box/tool box spare item. All that hard clear stuff below it is the backing/insulting material, they get hot and it melts out.

When they get hot it can make for a no start situation. Get a spare that matches the one you have now. Meaning where the "colored plastic insert located above where the wires feed out". Use some washers to space it off for cooling purposes.

Ignition modules, 74 (black grommet) and 75 (green grommet) are year specific and will not interchange. 76 to 79 (blue grommet) are interchangeable.
Ignition modules: 1974 is 1974 ONLY / 1975 is 1975 ONLY.
Blue module introduced in 1976 was used well into the 1990's.
D4AZ-12A199-C 1974 only
DuraSpark ignition modules identified by a colored plastic insert located above where the wires feed out.
2 others: One has a red plastic insert, the other has a yellow or brown plastic insert.
Red module is D7AZ-12A199-A used in some CA vehicles ONLY.
D9AZ-12A199-C (replaced D8AZ-12A199-A). One of these modules is yellow , one is brown .. Since the part number was replaced, I cannot recall which module was which color.
These modules were used in 1978/79 302 & 351M/W vehicles sold in high altitudes only. 351W: Passenger Cars & Econolines only.
1U2Z-12A199-AA (replaced D6AZ-12A199-B - D7AZ-12A199-B - D8VZ-12A199-A - D9VZ-12A199-A) .. Ignition Module - blue insert (Motorcraft DY-893) / Available from Ford.
Myriad 1976/90's FoMoCo vehicles.
Green Sales in OH.
Collectors Auto Supply in WA.
Haven Ford in KS.
Klimesh Motor Sales in IA.
Bob Allen Ford in KS.
Freese Motor Inc in IA.
Wesley Obsolete Parts in KY.
Dennis Carpenter Ford in NC.

 

Great, thanks 77&79F250 !

 

Wouldn't hurt to check your main grounds in this situation. Look at your battery, and follow the negative cable to where ever it goes. (Probably the engine.) Now look all around the engine to see if there is a ground running from the engine to the cab. There should be. They are typically found between a bellhousing bolt and the firewall, and are often a braided, un-insulated, flat cable.
Mine was missing the cab/body ground when I got it, but its symptom was that the starter was hanging up. All of the lights worked fine, but I've heard of a missing body ground causing all sorts of different weird symptoms.


Another theory: I wonder if someone swapped in a gauge cluster from a different year, and that the Instrument Panel Printed Circuit Board is different. Ford had a bad habit of changing them and their wiring harness pin-out often, even without any other apparent changes to the cluster or the rest of the vehicle. I learned that lesson on that above-mentioned '82 GT, when I threw in a '79 IP PCB, and nothing worked right... The IP PCB and the IP wiring harness(s) are a matched set, end of story!

You mentioned temperature and oil gauges, does the engine have the appropriate oil pressure sender? You can spot that at a distant glance, whereas the temperature gauge sender probably looks the same as the sender for a temperature warning light.

I wonder if someone threw a full gauge cluster in your truck, to replace a warning light cluster.

What gauge came, in addition to the fuel gauge, in the warning light cluster? Temperature?

 

I'm going to have a good look at the ground straps today. I'm sure I'll be adding a few to be safe and hopefully this will knock it out.

As far as the proper sending units, I don't know what or where to look. Can you give me an idea (Picture) of what I should be looking for and where? I have a Haynes book on it's way but till then I'm kind of winging it.

 

I said get the blue one by mistake. I re read your original post and seen you had a 74. I would say you need to get a black grommet one, that is 74 specific.

FYI ALL the info/list I posted came from Number Dummy from a while ago. But he is spot on with his info 99.999999% of the time.

Most parts houses sale a cheaper remanufactured option. Motorcraft is the best option.

 

I was rereading your post a bit ago, saw where you corrected it for my '74 and changed my response as well. I'm going to order up a spare to keep on hand. Thanks for all the help

 

Here's an oil pressure GAUGE sending unit:



That's where they are on a 302. On a 300, they are at the rear of the engine on the driver side.

It won't hurt to look and see, but I really think that the million-dollar question here is "what is the Ford part number on your Instrument Panel Printed Circuit Board?" And "is the connector making good contact?"

 

I have a 77/78/79 and always seem to have those years of application on the brain. Sorry for the confusion.

Carrying a spare voltage regulator and starter solenoid is a good idea too.

 

The oil pressure LIGHT sender is much smaller...