S197 Mustang HVAC Blower Fan Issue

I know we've got several S197 owners on here, so I want to post my recent experience in case someone else runs into it. I came out of work one day and the interior vent fan didn't work on any of the 4 speeds. No noise, no air, nuthin'. The vent selector worked fine - you could hear the flaps move in the box below the dash. This struck me as an odd failure. If the blower resistor goes out you should still have hi fan since that is direct voltage to the motor and bypasses the resistor, but no. Every vent fan motor I've had die made some kind of noise for a bit before dying.

There are several fuses in the system, both in the interior fuse panel and in the power distribution box under the hood. There's also a relay in the PDB. All of these tested good. I jumped 12v directly to the fan motor contacts and it ran fine, so the motor was known good.

I bought a blower resistor since it was cheap and put it in. No change. I thought perhaps the selector switch failed, so I pulled it out of the dash and checked for power. I was getting no power to the switch. After diggin around on teh Googles for a while I found on forum mention of a wiring harness connector with a burnt wire causing a similar issue.

Sure enough, if you pull the passenger kick panel trim there's a large white harness connector just aft of the fuse panel, right by the door. Most of the wires are small, 18ga or so....except the great big pink one that runs the blower. Sure enough that one contact pin was corroded and burnt in the harness. I cut the wire and bypassed the harness by installing a HD spade connector. I'm about halfway through the process in the pic below.

Works great now.

The other forum mentioned that this was a result of water leaking into the car, so I initially discounted the possibility since my car has almost always been parked indoors and I've never seen evidence of water leaks anywhere. Examining the connector, though, I think this is a result of the connector pin being underspec'd. The power wire is the only wire in the connector that is large - maybe 12ga? - but the pin is the same size as the others which have 18ga wires. If the fan needs that kind of wire ( and a 30A fuse in the PDB), I suspect the small pin was on the ragged edge of spec. It was also the ONLY pin in the connector showing any corrosion or scorch. I also suspect that never changing the exterior HVAC intake filter may have contributed by forcing the motor to pull more amps.

Anyway, I just wanted to put this up in case someone else is searching in the future.

That's pretty good detective work there ( I suck at diagnosing, so for everybody else that will say "that was easy" - it isn't to me...).

What year S197 was this on?

Haven't run into that one yet but thanks for posting, I'll watch for it.

In other S197 troubles, the KAM or Shaker 1000 battery drain was driving me berkeleying nuts, constantly charging the battery while seldom driven. Got pissed and installed new battery, WTF. Three months later and not being driven w/o so much as a maintenance charge it started right up tonight.

Still gotta do the driver door handle adjustment trick and still chasing a vibration in the driveline, right at the 60 mph sweet spot. Trying road balance next.

I'm not sure that a plugged up cabin air filter would make the blower motor draw more amps. Think about it like a vacuum cleaner. Without air to push against, the motor should speed up, dropping its current flow. Without air to help cool it, though, motor damage could result.

There's lots of undersized connectors out there these days. Dodge trucks of around 10 years ago have the same heater feed on the ignition switch, and it melts too.

Sky_Render wrote: What year S197 was this on?

2005, June build date. About 115k miles at the moment.