Ray,
get out your multimeter and measure the currently directly when the fans are on. I've measured a lot of electric fans over the last couple of years on the race cars to make sure I've got enough wire gauge to handle the load. I've never measured one over about 9 amps continuous, and these are some 14" and larger good quality fans.
If you've got two fans find out why they are drawing so much current. Or, if it isn't the fans get them off the circuit they are sharing with other accesories that are drawing the current.
I know there was a thread on
www.gt40s.com regarding the ignition switch sharing power with the AC compressor clutch etc. Your situation might be similar, it seems the CAVs have some screwy wiring in some builds.
I'd start checking those fans and find the true current draw. And if the fans aren't the problem through that circuit I'd find out what is drawing the juice. Might post again over on GT40s.com too, but put it in the electrical section, I bet it'll get more response. Not everyone reads the CAV section there.
R