The burning smell may be from the compressor clutch burning itself out, possibly by a short, or a crack in the insulation.

100 degree air temps mean pavement temps in the 130-140 range.

With the mileage on the vehicle, the compressor clutch simply may have died from old age.

-blaine

 

I would install coolant filter now!
It will get a head start on removing stuff and hopefully reduce the stuff you stir ip during the flush -your later.

Its possible you a/c compressor overheats from low refrigerant and then siezes up causing the smell and chirp.

Might have cascading of issues from one root cause.

Good luck

 

I was having this symptom also. My ficm just recently went totally down. For about 6-9 months I was having the pulsating lights on my headlights and dome lights. Just replaced my ficm yesterday. While the truck was down I had my alternator tested. Autzone tested it 3 times and it passed everytime. With the new Ficm from ed @ ficmrepair.com my pulsating is now gone. Maybe the ficm was pulling wierd power levels trying to stablize itself? But anyway, this may be your issue aswell.

 

So today I had some more time to look things over and get some help from a more mechanically inclined friend. The belt is still in great condition which rules out that scenario. What we determined, after jumping the compressor switch?, was that my clutch is fried. With that being said, I now have a few options:

1. Just replace the clutch and hope nothing else is wrong. Est $120 just parts
2. Replace the compressor, clutch and evaporator and have the lines vacuumed and recharged. Est $1,000 labor and parts
3. Wait a little while until I have the $$$ for bullet proofing and have it done then. My tech basically said that while the cab is off he can pretty much knock that swap out and won't tack on any labor. Labor $2,500 for everything including the studs. Parts can be bought on my own or through him for roughly another $2,000-2,500. (Not including ac parts)

The fICM I will most definitely use Ed for, I still want to check my batteries and alt before go that route.

I plan to install the coolant filter this weekend at the minimum.

Thanks again for all the help. What are y'all's experiences with ac clutch replacement and reliability? How does the bullet proofing labor sound? I bought this truck as a baby hauler/trip taker and want reliability....I am leaning towards the whole package but it is just a whole lot to take on.

 

My (limited) experience has been that it's far more difficult to find a mere clutch than it is to find an "assembled" compressor with clutch. Additionally, once you find it, the cost of the bare clutch is 50-75% of the cost of the combo. Compare that with the cost of recovering the refrigerant and evacuating the system. If you don't have the extra cash, the clutch by itself is the way to go.

Use these folks to get your parts:

Omega-usa.com Automotive A/C Air Conditioning

They have an extensive parts catalog, and the people behind the catalog(s) know how to use them.

I used them because when I needed parts, they were literally three blocks away. And they were cheaper than anyone else in town.

The clutch swap itself is fairly easy to do. You just need a clutch puller to do it. Those run about $40. Autozone rents them.

-blaine