In my ‘98 wagon a failed aux pump caused an ACC failure code but didn’t affect system function in warm weather. It was repaired before cold weather so I don’t know how it would have heated the cabin. I can’t imagine an ‘80s ACC system will seize to function altogether if the aux pump is removed. An aux pump electrical fault can fry the ACC PBU in early versions of post-Chrysler ACC.

Sixto
98 E320s sedan and wagon