A-C/cruise/PS woes - 1994 non-ZR-1 A4 Vette

[LilRedCorvette]

I'm hoping to get a gut-check/some thoughts on how to diagnose some issues that may/may not be connected because I'm about to lose my ever-loving mind lol.

The car: 1994 non-ZR-1 A4 vette, 170K miles. In other words, at the age where all hell breaks loose via electrical gremlins and hard-to-find parts make maintaining a 25 year old car 'fun'.

A while back I had issues with power steering not working very smoothly, and subsequently replaced the PS pump. Seemed to work for a while, then it turned out I needed a new rack. That is all back in, including red-line PS fluid, worked fine. Fluid turned black again, so flushed/refilled that. It seems like it's working extra hard (possibly due to the issues noted below)?

Also a while back the a/c blew hot, ended up doing a recharge, worked fine for a while. Then the problem resurfaced with it being the clutch switch going out. Replaced that and the a/c worked again. Now it's out again. Refrigerant level is fine, replaced the switch again to see if maybe it was defective, nope, a/c still doesn't work. BTW evap core replaced several years ago (the first time I had a/c issues).

It also seems that the power steering works better if the HVAC is set to off. Otherwise, it's very rough turning the wheel. The a/c clutch also now appears to seize/hang up when the HVAC is on, so I've been keeping the HVAC off so that it doesn't, and also so that the PS works, just so that I can even drive it.

I tried pulling the C68 HVAC codes on the unit, but it comes up with exactly zero. Sent off my original HVAC controller a while back to batee.com to refurbish, which is also back in the car, but these same issues are present. I've noted that when I start the car, it defaults to HVAC on and 75 degrees setting (which I have to immediately turn off so that my PS works/a-c clutch doesn't seize up the serp belt), and displays rather 'wild' outside temps (for example, "127 degrees", which decreases over time).

I've also noted that my cruise control no longer works and have in my forum searches seen that cc & a/c issues can be related. The vacuum lines are pretty rough looking and could use a replacement...but have also seen that some sort of vacuum check valve can be an issue (?)

The commonality seems to be they are all accessories connected by the serp belt, so I am wondering if the a/c clutch seizing up would cause the other accessories to suffer...also, if replacing just the clutch would suffice vs the entire compressor? Or is this solely a vacuum problem? Or both??

Sorry for the novel, but just trying to cover all bases with what I have tried. I am not a mechanic, nor did I stay at a Holiday Inn last night, but I do try to systematically rule things out as I go.

Any thoughts or advice would be appreciated!