Got my new to me blazer w/ bypassed core, I recently replaced it and the hard part I am now having difficulty to determine where the heater core hoses route to the core under the hood.

 

The core connection closest to driver side goes to water pump. Connection closest to passenger side goes to port on intake just behind alternator.

 

You can get both preformed hoses at a parts store. I got these from AutoZone. If you don't have holding bracket, I would suggest going to salvage yard.

 

Ok to be sure I have circled the ports here

 

Yes, but something looks a little funky on the intake port. My '98 hose is connected to intake under accelerator/cruise control cables bracket. Maybe previous owner added some fittings? Maybe it's just the pic.

 

Ok so I go the heater core installed it’s working great, found out the temp blend door actuator was faulty so I replaced it, the truck moves the actuator by itself in attempt to relearn but then fails. When I unplug the auto climate dial controller computer box, it resets and actuator starts to relearn but fails, and stays full cold no mix. This is the second actuator, first from Amazon second from orileys. I’m about to just remove the actuator and just stick my hand into the glove box when it’s pulled down to turn the blend door myself when needed lol.

 

 

Ok so in doing this procedure, the same exact condition is present, the system goes through initialization, then goes to cold only. I can feel the actuator moving with my hand when it performs the initialization, and when the truck is warmed up I feel the heat and cold from the ac go back and forth. After the initialization fails, the other controls work perfectly but the temp dial.

I just have the blend door arm grabbed with small vice grips so I can just drop the glove box and adjust the temp quickly that way

i suspect thermocoupler idk

thank you so much man

 

These pages are from my '98 TSM. Procedures may help you troubleshoot.

 

Also, you might want to consider going to Alldata https://www.alldata.com/diy-us/en and getting a subscription for your truck. It's $20 for a month, $60 for a year. Must have IMO when doing DIY. Colored wiring diagrams are nice also.