OBD2 won't work with '94 truck

[GMC-John]

I have a 1994 C3500 TD that has the OBD1 connector under the dashboard. My very trusty OBD2 scanner won't fit the OBD1 so I bought a converter cable that on one end has the OBD1 and the other has the OBD2. There is no response to the scanner because it looks like only 2 terminals on my truck's connector are even hooked up. Is there supposed to be any PO_ _ _
type codes offered in 1994? I do get the paperclip treatment to show a
DTC 36 but no other method to possibly display the PO_ _ _ style codes. What scanner can display PO codes from an OBD1 output connector, if any?

[DmaxMaverick]

OBD I DTC's are 2 digit. The 5 digit codes started with OBD II, 1996+. If you're only getting a DTC 36, then that's all there is.

If you only have 2 wires connected to your ALDL port, then you will have to power your scanner externally if you want bi-directional communication. Any non-CA Emission model 3500 with manual transmission has no need for all the other stuff that would normally be connected on other models or smog region.