I don't think it happens much (I have real bad luck, so...)
The main relay did go on mine. Truck died while getting onto Hwy.
Relay is located under the passenger side kickboard.
It has 2 electro magnet type contacts in it that controll fuel pump, EGR vacuum solenod, etc.
One of my contacts was all green with corrosion.
The cover of the relay can beremoved by bending 4 little crimps back. The relay gives no codes itself but mine gave bad ECU code on the highway before the expensive tow. I don't know where I got the idea to look at it, but that look was one of my rare lucky moments.
I resently checked Rockauto for the module, but they don't list it anymore. They had them on closeout a couple years back for $50. '89 is the only year for LX 122 ,the rest use an unavailable module.
I might need one too, cause I can't figure out what' wrong with my Raider,,,But I'm gonna replace cap and rotor- again- 1st. Not sure what brand to trust these days. Haztoys on another thread of mine seemed to be finding alot of bad caps and rotors while working at his shop.

TPS plug... igniter and or plug... pickup in the dist.. dist wiring...fuse link and wiring ... Come across some jumpered wires at the ecu alot too.. Not sure why ... Bad cap rotor..

"I" dont think the ecu's are as bad as the rumor is they are ...