Data Link Connector does not work
 

Is anyone out there can help me with a isse im having, My snapon scan tool will not connect to my truck(97 f350 crew psd) and i was able to get it to work then it disconected, so I check the fuses an none of them were bad and i checked the connector power, did voltage drop on the ground, and checked the bus + and- and nothing looked bad and my glow plug light comes on in the dash but im not sure if solenoid works and i never had a problem with starting it, but when i firt got the truck i plugged it in and it work and it told me some code cam sensor intermitent and i changed out the sensor and plug in to verify the fix and haven't plugged in since till yesterday when it was used it was winter now its summer. Does any one have any experience with this problem?

Does the truck run right now? Do you have the correct personality key in for a Ford K2A or K20? Does the scanner work on another vehicle? Another Ford? I have had the cable break one wire and then work on everything but a Ford.

does tour cigarette lighter work?
it has the same power source as the obd11 plug

X2 on the lighter. That powers the OBD11 port. It could be a fuse, if they are good, check connections.