Problem is, when air con is on--the tach quits below 1500 rpm. If the air con is off, tach works fine. Have tried two good tach amp (trash cans - on fender under the hood) and they both do the same thing. Any ideas as to a solution Where is Carnak when you need him (God rest Johnny Carson's soul) ?

Regards

Run_em

1983 300 SD

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1983 300SD - SPARKY THE DIESEL
2004 Audi TT 3.2 Quattro Roadster
1999 SLK - aka - LIL RED
1956 Chevy Nomad - aka - REAL MAD
1940 Ford dbl dr. Deluxe - aka - ORANGE U GLAD
1998 Kawasaki Nomad bike --

Just a stab in the dark, but possibly check the ground at the gauge end of things? Having another load affect an unrelated system always seems to point toward grounding problems, in my experience.

That being said, my tach bounces irregularly, so I can't claim to have a perfectly functional electrical system!

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-Josh
Testing the cheap Mercedes axiom, one bolt at a time...