Prof

OK, weird issue this morning - I get in my truck, it was chilly so I turned on the heater, and it came on then went off and then the lights sat and blinked randomly on and off...this was also moving the various vent arms too (could hear it), and then it would shut off, come back on, etc.

Turned off the headlights, no effect - turned off and on radio, no effect. The only cluster that it effected is the heater/A/C cluster and associated systems? Anybody have any idea what could be causing this? I did a search and this is a new one apparently. No rain recently, and I have never had this problem before - I am worried that all of this turning off and on will blow my blower motor or those vent solenoids or something - might this be a fuse issue?

Thanks!

ProjectSHO89

Check the battery and charging system first and verify system voltage is correct while the anomaly is occurring. If the system is under or over voltage, weird things can happen.

Prof

Thanks for the reply - would the battery system be causing just this cluster to blink though?

Can anybody tell me what the fuse is that runs this system? I looked at the fuse diagram and I can't tell if/which fuse would be in charge of the heater A/C light cluster and/or the system? It seems to me that there might be a short or something somewhere - would this be a #14 fuse issue?

Prof

Ok, here is the latest. I pulled a few fuses, specifically the ones dealing with the A/C (which went out a week or so ago), cleaned the contacts put them back. No change; when I flipped the ignition key I heard clicking corresponding with the flickering lights coming from the *fuse panel*, like switches clicking off and on corresponding with the blinking lights on the A/C Heater button cluster. What the hell is this?

needsmoarturbo

Have you checked the ground lug behind the passenger kick panel. It is common for it to rust away and cause odd symptoms. What you describe is not one of the ones I'm aware of, but I would take a look, it's easy to get at while you are in the area of the fuse box..

Prof

Where would that ground lug be exactly? I have been up in the fuse box and I haven’t seen any rust, but that doesn’t mean anything…

needsmoarturbo

Here's the ground location in my truck. This is what it should look like.

Prof

Thanks for the pic man, but I can’t make that out at all?

needsmoarturbo

The left side of that is the fuse box and the right side is the passenger door opening.
You just need to pull back the plastic kick panel

FMCovington

I had EXACTLY the same issue. Cluster was going nuts, and AC would blow hot air. Then everything would work fine. On mine, if I slapped the dash above the cluster nice and hard, it would usually work for a while--hours, maybe even a couple of days. Turns out that the 04-08 cluster PC boards have a notorious issue caused by crappy solder joints from the factory. It shows up after years of the sun's heat on the dashboard. The fix is actually easy, if you're handy with a soldering iron and patient.

Remove the instrument cluster unit completely, and touch the tip of a pencil-style soldering iron to EVERY soldered spot on the entire board, just long enough for the joint to "puddle up," then move to the next. You have to do the whole board--and you might want to have a little rosin-core solder handy in case you need it.

If you're not that patient or handy with electronics stuff, do what I did, and have a speedometer cluster technician do it for you. My guy came to my house and did the work in my driveway in less than a half hour for just over $100 nearly a year ago, and it's never so much as flickered since then. He said it is a common issue with older F-series trucks, and he had done it dozens of times.

Hope this helps.
Mike