Hi E-Type experts,

I am trying to help a friend with a '73 XKE 2+2 V12 who brought the car to me because of delayed gearshifts (Borg Warner 12). When cold, the transmission will not shift into third gear. Once hot, it will shift into 3rd, though not as quickly as it should. In doing some basic inspections I discovered that the kickdown circuit is shorted to ground inside the transmission, so probably either the solenoid coil or its wiring harness. I have disconnected the kickdown switch for additional testing of transmission behavior. The Workshop Manual fault diagnosis chart points to either rear clutch slippage, missing or broken sealing rings, or both, so a trans rebuild is in order and the kickdown solenoid can be addressed at that time.

In the process of assessing the transmission, I first discovered that if I downshift to 1st gear at a speed that causes the engine to rev to around 2,000 rpm or so, Fuse 7 (35A) blows and all of the instruments go dead. I subsequently discovered the same thing happens sitting in Park if the engine is revved to 2,000 rpm or so (this is an approximate guess - I haven't tried to determine the exact engine speed when the fuse blows).

According to the fuse box tag, Fuse 7 protects these circuits:

Horn
Radiator Fan Relays
Washer-Heater-Choke W/L.
Reverse Lamps-10/12V Reg.
Fuel, Water, Oil Gauges
Battery Indicator
Not listed on the tag but the schematic also shows Fuse 7 connects to the Tachometer

I've begun studying the schematic but thought some of you might help jump-start my diagnosis if you have any prior experience or good guesses as to what may be going on. I've searched the forums but haven't hit on a similar topic.

One observation is that through the tach Fuse 7 appears to carry current to the ballast resistor, ignition amp and distributor. Could the ignition amp be drawing excessive current when the engine reaches 2,000 rpm?

Thanks in advance for all ideas.

Cheers,

Don