Looking for some advice from others who have already been through this. My truck is a 1995 F350/460. My son's truck is a 1994 F250/460. In BOTH trucks, after you have started it up and driven for a few minutes the Check Engine light comes on. Resets itself when shut off, just to start all over again the next start. These trucks both are OBD1 diagnostics. I can buy an OBD1 reader from AutoZone and every other place, but I can also buy a cable that adapts OBD1 vehicle to an OBD2 reader. And there are several OBD1 readers and several OBD2 readers. And there is an OBD1 cable extension, I suppose so you can sit in the seat instead of standing next to the engine? So, not sure which way to go on getting something to read the codes on these trucks. Any experience out there dealing with these things?

 

Have you tried flashing codes on the check engine light? To do that put a paper clip between the STI and SIG-RTN pins in the EEC TEST connector under the hood and turn the key to run. That should put the PCM into diagnostics mode and a sequence of flashes should appear on the CE light, If nothing happens there is a good chance the PCM is faulty.
But if that works I suggest you buy the Equus 3145 code reader to take all the guess work out of interpreting the flashes.
I don't know of any OBD2 readers that work on this old system.

 

I would add that the cables for adapting are generally for purposes of adapting high end scan tools or people who have a lot of custom work. If the OPs CEL turns off at key off your computer is not getting its Keep alive power , so your trucks are likely behaving as if you are disconnecting the battery at key off

There is a fuse for this I believe

 

As far as I know, there is no adapter to hook OBD1 to a obd2 scanner. You can use a paperclip and the check engine light to check for codes for free, thou: as mentioned above.