adanvjr

Good evening,
This evening I started to hear a high pitched buzzing/whining noise coming from the fuse/relay box under the dash on the passenger side.

I noticed too that my A/C and fan controls were dead. Lighting on everything and radio was fine, but A/C nor AC fans would not turn on.

I opened the fuse box, laid a finger on the relay making noise and pulled it off. Noise stopped right after that.

The box lid said its "Relay 6".


This is the first I've seen something like happen.
Is it just the relay, or something more? (Hopefull not)

Any comments? Gonna try to head to o Reilly in a bit.

adanvjr

O'Reilly, AutoZone, and Advance does not carry the relay in stock.

1 week delivery time


Unbelievable......


Off to Rock Auto

lewissa81

Can you swap it with a different relay to see if it's the issue? I haven't looked, so I don't know if it's the same as any other ones.

Mod (Ret.)

According to the 2005 owners manual, relay number 6 is for the parking lamps, BSM, and Instrument panel illumination

Go here for a free PDF of your owners manual:

http://www.fordservicecontent.com/Fo.../05f12og5e.pdf

adanvjr

Parking lamps, instrument illumination light up fine.
I swapped the relay with a known good one and the buzzing started again.

I must have a short of some kind.
What is ideal place to look first?

It sucks because I got no heat.
When summer comes, I'm going to NEED that AC working again.

adanvjr

Update, got it fixed (I think):

Okay, so I swapped relays and the problem was still there.
I returned the relays to their original spots and decided to look first at the wiring to the blower motor and all connections were secure with no visible wiring short.

Since my climate controls (I have the Auto type, not manual dials btw) were dead, but no blown fuses, I decided to check the harness plugs behind it.
There were no visible shorts, but I unplugged them to see if maybe it was the control module that was acting up.

I cranked on the truck again and the buzzing stopped.
For further confirmation, I plugged the harnesses back in and the AC came on!

I'm thinking there was an electronic firmware issue within the board and it needed to be reset.

I let the truck run for about 30 mins to make sure all controls worked again.

Everything seemed fine.
Hopefully that was the case.

Time to go fishing.

susan2005f150

Thanks for posting this problem. I have the same exact problem. I had left my passenger window open the night before by accident and then had the buzzing problem. Read your thread and pulled the #6 relay and buzzing noise stopped but AC/Heat control head has no power. I am going to try to use a hair blower to see if it just needs to dry out and if that doesn't work I'll pull the harness as you did.

MyoldFord4me

Thanks so much for posting this problem and solution. I only just experienced the same thing. After much searching on the Interwebs, I came across this string. Tried it and eureka! Problem solved. Thanks again.