10A A/C fuse blowing when A/c Defrog is turned on
 

hello everyone!
Had a problem with overheating.fans were not coming on.after diags etc...duh...10a fuse/ac wasnt even present...put one in...fans working fine no overheating...BUT...now when I go to use the AC/defrost/fog...BOOM the 10a/ac fuse blows..immediately. possibilities? suggestions? I did notice some "grease" (grayish white) in the 10a/AC/FWD spots (specifically) AND in the 25A fan spots on the top left of the engine bay fuse box...this grease is present ONLY in those 2 areas...meaning it was put there I guess...any insights for fixes? (very annoying and actually kind of dangerous without the ac/defogger in the rain and the windows fog up)
I had heard that the compressor will "shutt of" automatically if their is not enough refrig in the system or if it is completely out(to prevent any damage to the compressor). when it shuts down...could this be via the fuse blowing to prevent use? I thought that was kind of extreme...but just a thought

Any help or info would be extremely helpful!

Thanks in advance!!

-Matt-

try unpluging your AC compressor and put it on defrost. If your AC clutch is shorted you will probly blow this fuse.

will definately try that...was thinking of that in a short line of other things to try as well...but i wanted a 2nd opinion on it. (and i didnt want to try it till i get a box of replacement 10a fuses lol)...i will report back on the findings!!

thx again!:)

-Matt-

To save yourself the cost of blowing fuses you could try connecting a high wattage test light across the fuse socket. If the short circuit remains, the light will illuminate at full brilliance, due to a the existence of a low resistance earth path.
Note that the light will illuminate at reduced brightness even if all is OK due to the presence of the normal connected load providing a resistive earth path.

ok...results:

disconnected AC compressor...engaged defrost/defog....fuse fine

reconnected compressor...engaged defog/defrost...fuse blown...

engaged AC with new fuse....fuse blown..

Im not AS suspicious of the grease that was in the 2 areas I had mentioned...because i think it is the conductive/insulating type (white grease)

what about the mention i read somewhere in these forums about if the AC system is low/out of refrig...then ...i cant remember what or how....does not allow the compressor to engage, to prevent damage to the system (cooling)....does or can it do this by blowing the circuit. Or is this something else.

Thanks in advance!
-Matt-

If you are disconnecting the compressor at a plug/socket close to the compressor the short must be within the comp. or within the wiring from the point of disconnection onwards towards the comp. There can be no other possibility.

This will not cause a fuse to blow. Check the A/C belt, if it's too tight it can cause a heavy load on the circuit and blow a fuse.

well time to buy your self a AC clutch. try to spin the center of the AC clutch. if it is locked up you will need the compressor also. (sometimes the compressor locks up and smokes the clutch) and if the compressor is locked up there is a screen somewhere inthe AC system ...youll need to replace it also. (it will have parts of your compressors insides in it)