Weird ASD relay and ECM problem

Ok, buddies truck.

97 XJ Auto.

Started out with an AC problem, charged the system with the proper amount of refridgerant. No ac, no power to the low pressure switch. Cooling fan runs full time and never shuts off. Not a relay problem.

Brush it off, other day fan stops working, fan tests fine. Yesterday, truck dies all together, get it towed, try cranking and it will barely run for a few seconds. As its doing this the ASD relay is turning on and off so fast that its vibrating. Tried swapping relays and no luck.

Safe to assume the ECM is bad?

Does the ASD relay on the 97 have the same part number as the other relays?

Point being, relays in the power box are common - swap with another one and see if it still does it.

The symptom sounds like something else more basic is causing problems.

DE DE DE question. What is the ASD?