94 348 air con question/help needed.

I am troubleshooting the air con system on my 94 348. With the key switched on (engine not running) the pressure switch on the dryer does not have 12vdc on any terminal. First step is checking fuses. The 10 amp in the passenger footwell is good as are both 20 amp in the luggage compt. Can someone please tell me where the primary 30 amp fuse for the AC system is located.

Symptoms are with the key on and AC i can hear the baffle shift when different air directions positions are selected. Temp. LO selected and the fan speed selector goes to full out on the indicator but the fan does not start. Any suggestions appreciated.

Regards,

Brewman

Beer is proof the God loves man

 

This one?

http://www.ferrarichat.com/forum/technical-q/369331-355-c-hidden-fuse.html

(Yes, the hidden fuse is also in the 348)

 

And another . . .

http://www.ferrarichat.com/forum/348-355/150994-help-again-sorry.html?highlight=A%2FC+amp+fuse

 

Thanks to Chas-3 and Daniel at Ricambi for providing help in finding the hidden 30 amp fuse.

I found the fuse had already been replaced with a Bussman 30 amp fuse and it is good. It directly feeds the evap. Fan relay and then branches off to other locations. The relay has also been replaced with an aftermarket 40 Amp relay p/n 1208 SH049. Google search identifies this as a 40 amp relay used in several different applications. The plug for this relay shows signs of heating but is solid and the terminal are clean and tight to the relay pins so I think it's good.

I took the cover off the the relay and it shows signs of rust/corrosion and the NC Contact is off center and making little if any contact internally. It also has a distinct odor of being hot.

I'll get a new relay, no problem here. Of more concern though is there are 4 relays mounted on the a module beside the fan. All have a fuse installed except for the relay closest to the front. The fuse for this relay has been removed. My WSM does not sow these fuses so I'm not sure what size it should be or what the relay does. Any help with this is greatly appreciated. This is black relay with white dot shown in the pictures.

Thanks in Advance,

Brewman
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That's part of the ABS system. That empty fuse is supposed to be like that. You put a 10 amp fuse in there only to pull error codes from the ABS computer. The other 3 relays in the row are also part of the braking system.

 

So is the problem that the ventilation system fan isn't running, thr evaporator fan isn't running, or is it that the A/C compressor clutch isn't engaging?

 

Once I replaced the fan relay it now runs. I have to check further to see if the compressor clutch is engaging and evap fan running. I am planning to jump the pressure switch contacts later today to check this. I've also noticed the clutch relay has been replaced so someone has been here before.

Any recommendations appreciated and thanks to those Fchatters that have responded so far.

 

Just finished jumping the contacts on the pressure switch and both the evap. fan and compressor clutch work. Next step is to test system pressure once I locate the test port.
I thought it was in the area of the ventilation fan/pressure switch but don't see it. Will search Fchat for info. on this.

Thanks again to all who responded to my original post. The Fchat community is great.

 

Test port is near the expansion valve. Under the front trunk carpeting -- nearish to the drivers side of the vehicle.