Indicator/Turn signals don't work on hot days
 

I have a 2005 E-150 Club Wagon Chateau 5.4L V8 Auto.
When the air temperature inside the van is warm or hot, the blinkers do not work. If I turn the a/c on full blast while driving they *sometimes* start working again, until the van warms up.
On cool and cold mornings they work fine. By the afternoon they do not.
We live in Texas = lots of hot days.
This problem has been there for several years - the dealers are unable to replicate it - they drive it early in the morning when it is cool.
I have replaced the flasher unit. It worked - until it got hot then it did not. The original one worked the next morning too - till it got hot.

I suspect that the fuse box - near the driver's foot - was kicked and is damaged in such a way that when the air is hot and some expansion occurs that a connector breaks. My fuse box does not have a cover over it - If it originally came with one then a previous dealer service department must have lost it years ago.
I have replaced the fuses - makes no difference.

I am contemplating replacing the whole fuse panel, but wondering if anyone else has ever experienced this?

Thanks in advance

Yes , I have ! Ran another supply wire to the flasher because the problem was behind the fuse panel. This vehicle had the windshield replaced and as the rest of the story goes , then it leaked . When that happens the box/panel starts doing crazy things.
You are on the right path, go for it !

Fantastic news! I hate to be the first or only person to have a problem.
We had the windshield replaced within 3 months or buying the van new. It leaked where the temp gauge is above the mirror. We had it replaced 3 times - still leaked. Eventually we resealed it ourselves and decided it was a bad build quality as 3 diff windshields never fitted properly.

So was your solution to run another wire to the flasher unit? Did you replace the whole fuse panel and if not where did you connect the wires - I understand if you can't remember the details but glad I am not alone in the problem.

Did you perhaps also have intermittent usage of the cruise control at the same time?

This particular problem was on a F550 for a township. The signal and hazards worked when they felt like it . Took a while to pin down the problem since the electronic flasher had 5 terminals and first had to find the flasher up in there then spliced in a fused feed to the flasher. The problem was insufficient power coming out of the fuse panel due to corrosion. It had no cruise control, but the darn wipers would quit when plowing during a snow storm. All because of the leaky windshield and fuse panel corrosion. Its a project , but would be better if you replaced the entire panel because other problems are "waiting in the wind".

Thanks for the response - any idea what the part number would be? I am hitting eBay but tough to know if I have the right part. Is there perhaps a cheaper alternative than my Ford dealer? I am trying to find a parts diagram online - I will likely need to find a service manual or at least the Haynes manual.

Many times a cooperative Ford parts dept will give you the correct part number.
To do this they will require your vehicle's VIN . Not sure if there are any/many variations available.

Thanks
 

Thanks - looks like a job for the winter - or at least before Spring :)