71 Vette - no "high" on blower fan issues
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
I didn't know that (or, I forgot it from earlier in the thread). Soooo, that boils it down to a defective 'new' components or a 'problem' created during the installation process.
Yes, you can check the relay. If you have a copy of the Chevrolet Chassis Service Manual, there is an electrical schematic of the A/C-heat system in the Accessories and Air Conditioning section. You will need to use a volt-ohmeter to test for 12v (or reduced voltage if going through the resistor pack) signals being switched on to various relay terminals in order to test the relay properly. And make certain that you ground your VOM at the same point the relay uses; then if you get improper signals, you can re-ground it at a known good grounding point (-battery line??) to see if anything changes. It could be a grounding problem, too. For the wiring harnesses, use the ohmeter to check for good continuity of each specific wire and to test every other wire in the bundle that they aren't shorted to that one being tested. [Yes....ALL of them.} Then, verify that the connectors at each end are manufactured as expected and that they are making good connection. All of this is not easy (when done by the purchaser instead of the manufacturer
), but it is absolutely necessary with a problem such as yours.
Yes, you can check the relay. If you have a copy of the Chevrolet Chassis Service Manual, there is an electrical schematic of the A/C-heat system in the Accessories and Air Conditioning section. You will need to use a volt-ohmeter to test for 12v (or reduced voltage if going through the resistor pack) signals being switched on to various relay terminals in order to test the relay properly. And make certain that you ground your VOM at the same point the relay uses; then if you get improper signals, you can re-ground it at a known good grounding point (-battery line??) to see if anything changes. It could be a grounding problem, too. For the wiring harnesses, use the ohmeter to check for good continuity of each specific wire and to test every other wire in the bundle that they aren't shorted to that one being tested. [Yes....ALL of them.} Then, verify that the connectors at each end are manufactured as expected and that they are making good connection. All of this is not easy (when done by the purchaser instead of the manufacturer
), but it is absolutely necessary with a problem such as yours.
