Thanks for that! The kicker is that so far, local parts house Autozone only has the two prong sensor in their database, ( SU 381 or WT 3026 or TS 82261) They don't seem to have a # for a single pin temp sensor in their database (-yet!)
The single wire sensor proves out by the momentary ground test ( you have to put a paper clip/ pin or thin wire in the connector cap to get a reading) Kragen stocks the single pin Niehoff TS 73821. While I go there, might as well replace both for about $10 each. Another single pin temp sender is made by Standard, # TS271 ( obtained @ Allied auto supply, Pasadena Ca)
also Pep Boys: Borg-Warner wt427 single pin

Note: if the temp registers high, it might NOT be failure of the thermostat. In this case if the two wire sensor ( the one at the center front, on the other side of the radiator hose from the passenger side single prong sensor) has failed, the electric fan doesn't come on when it's hot- & this will send temp out of range.

Amazing that this is the only reference (that I found at any rate) on the web so far to this specific information. Your simple note may help a lot of folks over time. Many thanks!

 

(corrected my earlier post, thanks!)

 

The dealer should have it. Since the same sensor was used in many models for many years, they might even have it on the shelf.

 

Hi Alloro,
I'm kinda stuck here in the process of getting that temp sensor replaced. Had gotten as far as loosening the top & bottom bolts on the alternator, only then realized that unlike the haynes photo in the alternator section, there does not appear to be any familiar sliding slot- belt adjustment bracket. Looking from on top or below, I only see a spring tensioner with no visible adjustment.
( update)
found the serpentine belt adjustment procedure; it's a 15mm bolt turned CW to loosen the tensioner
( access issue) It looks like it will be fun trying to nudge it, & get the belt off.
5 minutes, tha man says. all righty, then...
Am considering taking off the fan shroud but it doesn't look like that will help much.

 

There are no slots on the alternator to slide it, it's fixed in place, the tensioner does all of the belt tightening. You have to pull the tensioner pulley over to the right with a 15mm wrench or socket/ratchet and slip the belt off the top center idler pulley (the smooth one without any lips on the edges). After the belt is off, the alternator can be pulled out of the way. I recommend disconnecting the negative battery cable first, just to avoid any accidental shorting of the battery post on the back of the alternator to ground.

 

Yup, battery terminal off FIRST.
Well, hope this update may help someone else avoid what I did run into. As the belt tensioner seemed to be hard to move, & I wasn't in the mood to remove the fan shroud for better access, opted to remove the sensor from above with a deep socket. The old one came out with a 1/2" socket but the new ones are 9/16". It wasn't that hard to get to with a long extension. However on installing the new one, made the mistake of waiting for there to be a little resistance which never came, & I snapped the brass case, breaking the sensor! thin wall, too. sigh. At the time was using a 1/2' drive; a 3/8" is the better choice here. Got it extracted & a 2nd one installed. Don't think I'll make that error again!