Short Circuit

If you got the ATO unit from Pantera Electronics I’m sure Jon would help you figure out what’s causing the problem.

Mike

Yep I sent him an e-mail to see, any one who wants to chime in is welcomed

Well, the A/C compressor power wire and connector is very near the alternator. Might want to see if the connector came disconnected and is shorting to ground.

Mike

What color is the wire ?Will I be able to acess the wire from the bottom without having to take out the front engine cover?thanks

quote:

Will I be able to acess the wire from the bottom without having to take out the front engine cover?

Best way to get to the engine bay wiring is to remove the center engine screen, and then the passenger side engine screen. This gives pretty good access, from above, not underneath.

If you also have the passenger side rear window removed, you can reach all the wiring even easier.

Larry

Or jack up the rear of your car, remove the right rear wheel and the splash panel (three screws). Pretty easy access to the firewall wiring, spark plugs, back of the alternator, A/C charge ports etc., through there too, unless you've moved your battery into the way.

Looking at the wiring diagram for a late and early Pantera, fuse 10 supplies power to just the ac condenser and ac clutch relay coils which are under the dash on the drivers side. The power to the ac condenser fan motor and the ac compressor clutch themselves is supplied by fuse #7. If everything is wired correctly, the problem is not with the compressor or ac condenser fan.
Fuse #10 also supplies power to the blower motor which is via the oblong switch. This is the evaporator / heater blower motor. Is this the switch you turn on that causes the fuse to blow?
Panteraplace is a great resource for electrical diagrams.
http://www.panteraplace.com/page107.htm

Yes when i turn on the gauge which turns on the blower motor the fuse blows

Sorry I mean when I turn on the switch which turns on the blower the 30 amp fuse # 10 blows

Jon is VERY good about helping!

One thing I would test, if you are SURE the wires on the F10) terminals are BROWN and the fuse blows when you turn the FAN on only. THEN I would pull the 2 wires and test the fan circuit away from the fuse panel. First with an OHM meter to check for ground or short then an operational test. Use an inline fuse or breaker for this testing. If your inline fuse blows, the problem is in that circuit which you can trace back. If the blower runs fine, I would check that the bottom of the fuse panel is insulated from the chassis with the plastic shim that was under your origional fuse panel. Then I would very carefully check the wiring, wire for wire on the fuse panel before reinstalling.

Good luck, let me know what you find. BTW what ignition system are you running? Factory, Duraspark, MSD?

Angelo

quote:

Originally posted by bdud:
Looking at the wiring diagram for a late and early Pantera, fuse 10 supplies power to just the ac condenser and ac clutch relay coils which are under the dash on the drivers side. The power to the ac condenser fan motor and the ac compressor clutch themselves is supplied by fuse #7. If everything is wired correctly, the problem is not with the compressor or ac condenser fan.
Fuse #10 also supplies power to the blower motor which is via the oblong switch. This is the evaporator / heater blower motor. Is this the switch you turn on that causes the fuse to blow?
Panteraplace is a great resource for electrical diagrams.
http://www.panteraplace.com/page107.htm

Nice work bdud!

It is always best to check Pantera Place before trouble shooting these machines. I was working on a nasty brake problem last year and was trying to find out how the proportioning valve worked. Had no clue where I could find something like that, so I Googled “Pantera brake proportioning valve” and there it was right on Pantera Place including pressure graphs and all. Totally amazing!!!

Mike

Guys, since you've changed fuse blocks, I'm not sure if this is relevant, but be aware that the screw that retains the fuse cover door is the same thread as those used to hold the gauge console panel in place EXCEPT IT IS SHORTER! Using a longer gauge-panel screw to retain the door can allow the threaded shank to penetrate past the retained nut and far enough inside to intermittently short fuse 7, 8 and 9 on a stock fuse block. This tip was published in the Dec 2009 POCA Newsletter, from Nor-Cal owner Jim Murch.

Good point, I have found also that the fuse panel is actually mounted in different locations, up or down between cars. Mine now, I had to remove the glovebox and drill a hole to even reach the top fuse panel screw because the panel is mounted so high! However, I think that screw would short anywhere from 7 thru 9 fuses in normal mounting positions, could definately hit the top corner of the ATO fuses of mine. Thanks for bringing that up, I need to check mine when I put things back together this weekend. (I hope).

Angelo

Figured it out! Had loose ground of blower resistor. Thanks to all!