Rad fan stopped spinning up leading to several overheats, one of which blew the sidewalk off the radiator.

Radiator replaced, relay replaced, coolant temp sensor replaced, rad fan replaced

If I bypass the relay to a switch the fan runs perfectly fine, I just have to monitor the temp and remember to shut it off when I get out else it kills the battery

Only parts left that could cause it are the relay base or wiring to the ecm or a faulty ecm not passing the signal to the relay

Anyone know where to find a new base for GMs wonky *** mid 90s relays as I don't really trust a junkyard pull for this

If that'* not the solution I'll have to swap ecms at $200 a pop which I'd like to avoid.

Can't edit post.

Blew the top 1/3rd of the sidetank off the radiator by the upper hose connector

You likely blew a head gasket if not worse.I have the factory info for your vehicle. Do you have a good scan tool? Live data? Need special software to read OBD 1.5

No head gasket issues, runs fine otherwise.

It'* not obd 1.5 it'* ALDL and I have a scan tool for it

It'* OBD 1.5 so you must have the correct software for it. Look at the CTS and it should command the fan at 220 or so.

I'd check at the contacts for the relay. See if signal voltage is arriving at the contacts such that the relay would send power to the fan.