2G No power to HVAC unit

[sebastian81296]

Hey guys, i have been chasing down some sort of electrical issue on my 98 GSX and I'm needing some guidance from someone who maybe has gone thru similar.

Currently my HVAC control unit under the radio isn't getting any power. No fans speeds thru any setting. I have already verified all fuses related to the AC both in cabin and in engine bay are good.

I've verified I don't have power to the blower motor, and I've already switched out the blower motor resistor behind the glove box as well as the relay under the driver fuse box. Is there anything else or any other component I should check out before yanking out the HVAC unit?

Whole thing happened due faulty alternator voltage regulator which caused some fuses to blow while driving. Since then all fuses were replaced as well as the alternator.

Is there an ECM that sends power to the HVAC unit? Any insight is appreciated!

 

[TerminalTalon]

Have you pulled it out yet to check power to it? Do any of the lights work?

 

[sebastian81296]

Have you pulled it out yet to check power to it? Do any of the lights work?

Hey what up man! Firstly thank you for giving your input!

Absolutely no power going to the switch. I did also find that the “high” setting wire had burnt thru its connector. None of the other pin outs had power going to them as well.

I was looking into the A/C wiring diagram and I saw that the “high” setting black and yellow wire comes into junction with the blower motor wire, so maybe there's a break some where there? At least I can verify there's no power to the connector to the blower switch. Also maybe could be a ground circled in the pic?

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[TerminalTalon]

So the highest fan setting is usually default when the resistor or control unit goes bad. If something has electrical tape on it check it. I see a couple things that are taped.
Can you spin that fan freely? Can you put power and ground to it and see if it works?

 

[steve]

There isn't much difference from what I can tell but lets use the 2Gb Turbo diagram and walk through it.

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Power (battery voltage) for the Blower Motor comes from Fusible Link #2 goes through Fuse #11 to the Blower Motor Relay when the Ignition Switch is On to the Blower Motor pin 1.

The Ground for the Blower Motor comes from Grounding #5 to the Blower Switch pin 5 and depending on it's position through zero or more of the Blower Resistor elements to the Blower Motor pin 2.

So first check would be do you have power to pin 5 of the Blower Motor Relay?
Do you have a good ground at pin 5 of the Blower Switch?

Second do you have power at Blower Motor pin 1 with the Ignition Switch on?
Do you have good ground at pin 2 of the Blower Motor with the Blower Switch on HI?

The answers to these should identify where the problem is.