Heater & A/C blower doesn't work on high speed

[batcomm1]

Or is that strictly a "junction " and needs the posts "tied" together....

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[bd]

Seems you found the problem.  There is no hidden internal connection between the two posts.  The posts should be bussed together with an unfused jumper and tied directly to B+ via a 12-gauge red wire connected to the starter solenoid 3/8" battery cable stud and a 6" long 16-gauge fusible link located at the solenoid end of the 12-gauge wire.  At this stage, you should trace and take inventory of the wires connected to the firewall junction block to determine whether someone has reconfigured and rerouted the factory wiring so that you do not inadvertently introduce wiring conflicts that might result in an electrical fire.

[batcomm1]

Just did an LS swap into the truck so it's a good possibility that I did something...been a long process... I wantbto thank you for all you help and patience with me and my questions, now I get to start the process of integrating the 2007 ac compressor on the LS to the stock stuff on the 84 Silverado...load of fun for sure!

Again, thankbyou for all your help!

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[batcomm1]

I was told I needed to install a high pressure switch inline on the high presser side also, gotta try and figure that one out also

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[bd]

There should be multiple options to accomplish that task, including custom hoses.  Good luck!

[batcomm1]

Yup that's what I'm reading on now!

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