I have BODY and CHASSIS manuals for through 2004 also I'm sure. There's Tech1, Tech1(a) and also MT3100 in that manual. GM Vetronix Cable / Cord for Techline Tech 1 Diagnostic Scanner Scan Tool 6 ft. See the GETTING STARTED section page 131 of the manual for various configurations.

I have the alligator battery clip style I believe still NEW. It looks like your cable has the provision for the 12V either cigar lighter or battery clip adapter that's required. The manual I sent is Vetronix and I don't know that I can convert the Vetronix #'s to those of the GM Tech1(a) when supplied by GM. New GM Vetronix Test Probe for Techline Tech 1 Diagnostic Scanner / Scan Tool. Now, before you rush right out and buy one, heres. Find great deals on eBay for gm tech 1 scan tool. The file is sent and when I unlock more I'll send them also. The net result is that a number of Chinese vendors are offering Tech 2 scan tools at hobbyist price levels. Once it's 'unlocked' I may post an image.

pdf is (secured) so I'll unlock it before sending. I'm sending you a complete Tech1, 1(a) and MT3100 user manual to sort through. GM’s Tech 1/Tech1A, Tech2 and GDS2 scan tools are assessed. Sounds like you only have the Tech1(a) and the actual DLC cable, there's a DLC to 16 pin OBD2 cable that would plug in to it or a different cable in it's entirety. BOSCH Automotive Tools MTECH2 Mastertech II J2534 VCI with Wired/Wireless Capability for OEM Reprogramming and Diagnostics on GM, Ford, FCA, Nissan/Infiniti, Honda/Acura, and Toyota/Lexus Vehicles. GM Techline Tech 1 Scanner With Cable And Mass Storage Cartridge. No MASS STORAGE UNIT cartridge or other software and no way to plug it into the 16 pin DLC connector.

G m tech 1