Well, about 2 months ago, i was driving i had my heater/blower on since it was cold ( it was on economy at full blast). My ac was not working because it did not have freon. All of a suddent as i was driving, the thing that blows air into the vents stopped. I was almost home so i figured ill check it out tomorrow.

Well fast forward, it has never been working again. No more air from the vents.

Now i want to fix my AC, my compressor does not engage, my blower does not blow, i took off the blower ( the thing that spins on the passanger side) and i took off the wires, and put it on my electric read out ( a light bulp) it did not light up. I went to the front of the compressor, did the same, nothing, i checked rellays, nothing.

Where else should i check ? this thing is driving me crazy! I would like to get this fixed before summer school starts. I would appriciate any advice/tips on how to check whats working and wahts not.

So far it seems like my :
Blower does not work
AC compressor does not engage
Fan infront of the condensor does not engage

So im guessing something is mest up with the cooling/heating system--but i have no idea what! Thanks guys before i g o

Replace the bad fuse.

the fuse looks good....i switched the relays and same problem..

Which fuse/relay do you think it is ?

Do yourself a big favor. Before you do ANY more diagnostic work go down to your local parts vendor and get a full set of fuses for your car. Mercedes Fuses are known for corrosion issues and while they might "look" good they might not be providing a good connection. Also don't do the glass fuses. They never work quite right and have a tendancy to blow frequently.

I had a number of electrical issues in my 300SD that completely went away with new fuses. They are cheap and will save you a ton of headaches.

i just went out to do as you said

I replaced all the blue ones
Red ones
and about 75% of the white ones

I ran that light bulp thing to see if it was getting current... its weird If i have the positive thing touching one fuse and touch the same fuse- it dosent light up, if lights up with only some of them that i touch ( other then the one im touching with the positive side)

is that the way it should work?

Is the key in RUN? Some circuits aren't live when the key's out.

Sixto

The fuses are usually run on the positive side of a circuit so touching your light to both ends of the fuse does nothing. Vehicle electrical systems (in most cases) are 12 volt negative ground meaning that you can get the negative side of the battery by touching any part of the metal frame. If you put one side of your lightbulb on a metal object thats grounded and then touch it in the fuse box you will be able to do your testing.

Better than a light bulb would be an VOM to measure the conductivity/resistance of the fuse. Additionally if your only getting 2v at the end of your circuit it might be enough to light your bulb yet not tell you your missing 10v of power. You can get a cheapie at radio shack for $10.

Just for future reliability I would finish the rest of the fuse box as it will save a lot of future headaches.