No mode selection after water pump and thermostat replaced. Developed temp gauge fluctuation and heater banging noise. Solved by OE stat and pump replacement then this issue developed?? Any help or suggestions??

 

Ranger's have known issues with the Blend Door, google: ranger blend door

This wouldn't be related to water pump or t-stat through, and these are not related to Selector switch inside the cab, there really is no cross-over as far as I know.

Did you disconnect a vacuum line, maybe by accident, when doing the engine work?

 

Thanks for the input Ron. No it started with a coolant leak (shop replaced tstat and pump). Then temp gauge issue with thumping from heater developed afterwards. They replace 3 tstat and then finally the water pump (all now OE) as I suggested after the first tsta. Since then the mode selection issue developed?? I've been back 5 times but no more!

 

There should be a vacuum diagram on the rad support, have a look there for the vacuum lines for the Selector, usually they are "hard" colored lines not like regular soft black vacuum hoses.

They are often connected to a vacuum reservoir(can) so it can operate even when engine vacuum is low

 

I found the black ball with 2 hard lines

 

I found the black ball with 2 hard lines laying against the r/s exhaust manifold. One of the lines melted off, the ball was ok.
Repaired it with a washer line from my scrap 00 Buick.

 

Good work

Thanks for posting the fix