Larry,
I cannot figure out what you mean about an arrow on my 603 belt tensioner. When I look in the service manual it only describes checking the bearing pin for firm seating and that the collar of the bearing pin must contact the timing case cover. And that the idler pulley must not exhibit any alignment faults. And it also says these parts must be checked on the 1st design up to 10/85 with no mention of what to check on later production.
Anyway I am still suspicious of the compressor or another pressure switch. The dealership changed the switch which was located right next to the drier. I don't know if that was the hi or lo pressure switch. I will look it uo and maybe have the other one changed out. The A/C quit again today on my wife as she was leaving Target. It always happens after the engine is good and warmed up, then shut down for a short time. I know from experience that the highest head pressures will be encountered during that scenario.
I appreciate your help very much. By the way, do you know anything about the Isuzu NPR equipped with the 4 cylinder diesel?

__________________
Brian
87 300Dturbo 180K #14 head still running R-12 SOLD 12/2017
02 F350 Powerstroke 180K
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08 Infiniti FX-35 40K
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10 Sprinter 3500 chassis with a Class A Winnebago on it. 56K