My 90 740 was doing that, replaced 1323592 Noise Suppression Relay (AKA: Radio Suppression Relay or "RSR"). fixed it, replaced relay and relay connector, both relay and connector were bad, I just used a relay with the same specs., cost a few bucks, works the same as the 65 dollar one.

I threw on a generic o2 sensor and taped off the heat wires, now got a 212, wonder if it's from the ecu not getting the heat wire signal?

Thanks Lummert.

Trying to figure out which carrier bearing and support I need for it, the driveshaft is 2 inches diameter.

Could try checking voltage at the fuel injector connector with multimeter, ignition on engine off, black lead to ground, red lead to connector, should be about 12 volts, I checked mine with connector off.

Are the front bearings the non service type on these?, it has the axle nut that you hit to secure it, got it off with lots of effort, no cotter pin type nut. I took it apart and can see the bearings, the bearings that auto zone had, that was suppose to match, seem way off in size and form, for about...

On my 90 gle, number 9 fuse is for turn signal, number 2 is for hazards, did you check your fuses? sometimes they look good but are bad, try swapping a same amp fuse from another spot, if you haven't looked at fuses yet.

it's from the ecu.

Odd, when I turn the heat selector all the way right, full defrost setting, the ecu squeals constantly but when it's in the other 2 or 3 positions it doesn't squeal at all and when the heater is set to off, ecu squeals, very strange.

Could try checking voltage at the fuel injector connector with multimeter, ignition on engine off, black lead to ground, red lead to connector, should be about 12 volts, I checked mine with connector off.