1990 C4 L98 ZF6sp Z51 Engine Control Module & Tach
 

So I had some work done on my car, brake line and battery replacement. Immediately after this my tach stopped functioning. Pushed in all the terminals, came back for a little bit then stopped working. Is there anyone familiar with the Engine Control Module on the 1990 L98 which is different from the 89. mounted above the battery that can tell me which of the connectors contains the path for the tach? I have had this problem before and corrected it changing the ECM but wondered which module is my issue.