This assembly was called a power stage in 1989 Rex
and in 1993 Rex "Power amp/Ignition Coil"

The pinout in the Volvo pocket data book is for the B230FT
that has separate coil and power amp

Steve, Put the coil back in and test DI assy with your meter.
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Rex-I Distributor Ignition (DI) system (B230F) or B230FB
B for Bendix
schematic from 1993 940 manual

Pin out for Power amp/Ignition coil 4/26

_____________ HT_____________

C__B__A_____B__A_____C__B__A

1__2__ 3_____4__5

1 To Tach red/white
2 Signal ground 31/32 black
3 +12vdc from ignition switch blue
4 from ECU pin16 control voltage green
5 Power ground 31/33 and ECU pin 20 brown

To test coil pack
Rex-I Bendix (#1367438)

Measure between primary
Pins 1 & 3 _____ 0.5 - 0.6 ohms

Measure between secondary
Pins 1 & HT______5.0 - 7.0 K ohms

HT = High Tension wire to distributor

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It's interesting that the B230FT the RSR shuts down
the 12VDC to fuel injectors AND the ignition coil

The Rex RSR shuts down only the Fuel injectors

Steve was getting wet plugs so it still looks like ignition.
His connections between the coil and the 5 pins are bad
and maybe the power amp is the culprit here?
Can it be serviced or replaced separately?
The coil is available separately.

I asked Steve to check for no air in case he sucked a plastic
bag or a raccoon into his air intake, all is well there.

I don't have the engine schematics for 1991 so maybe Steve has
the Fuel relay and RSR to worry about which he can test by
making sure he has +12VDC at pin 3 blue wire

Bill