RE: July posting - Constant 12 Volts with KEY in OFF position.
Thanks guys.
Sorry I’m late in following up on this. I had put this project on hold but have recently continued pursuit of a solution and have now finished the project. My A/C power and Radio power are now provided power ON by a remotely located switch in the cabin – independent of the Ignition Key switched power. The #2 Fuse block was removed and replaced by two relays that provide the two units with fused 12 VDC power.
I was able to acquire a copy of the Frigiking A/C installation manual. Regrettably, it contained no helpful information. The only comment about the electrical connection for the A/C unit is on Page 11, step 10, that contains this statement, “Connect the Power Wire (10 ga., Red) to the upper terminal of the #2 fuse holder. (See inside of fuse box cover for location of terminal).
No such info exists on the inside of the fuse block cover.
In my situation, the A/C installation with the color and size of the wire assumed to be that of the load side of the fuse block at the #2 fuse holder (bottom wire) is Black/Red, size 16 AWG – not Red 10 ga. When this wire is provided with 12 VDC, it powers up both the A/C and the Radio with ignition Key OFF. That wire was connected to the bottom lug of the fuse block. From what I was able to figure out, this wire enters the firewall just aft and to the right of the engine block and is tied in (under the dash) to the power IN connection at the Frigiking unit. I think this explains why the wiring from the fuse block was overheated because the A/C power drain by the A/C when running is in excess of 25 A. and to support that, should have been at least 10 Ga. in size. 16 ga wire is of insufficient area for that amount of current drain and can only safely conduct about 10-15 A, assuming a short distance run of about 8 feet .
Behind the glovebox, there is a wire labeled “Key B+” (assumed to be originating from the ignition switch) where there are 3 wires twisted together in what I call a Yellow “Bombtail” connector. Torquing this device onto the twisted together wires till it’s tight supposedly provides electrical integrity for the conductivity of the junction for those 3 wires. It should have been a soldered connection. Back to the fuse block though.
The existing top wire of the fuse block (i.e., the load side) does happen to be a 10 ga. wire. However, this 10 ga. wire color is Black/Red (not solid Red), making me believe that the technician who re-installed the Frigikiing A/C system after its removal in 2014 for overhaul by Bud’s Benz, may have erred by not using the existing 10 ga. Black/Red Wire from the fuse block to the cabin area and instead had connected the 16 AWG wire from the fuse block (upper terminal) to the junction of the Frigiking’s 10 ga. wire and the 18 ga. wire for the radio power on circuit. It’s not possible to get visible access to the hole of the Frigiking cabin unit where its wiring exits the unit. But, the 10 ga. wire (from the A/C Unit) of this 3 point junction where the radio power, A/C power and 12 volt source are tied together is White, not Red. My assumption is that the pre-existing 10 ga. Black/Red Wire from the fuse block is capped off behind the dash - (probably done so at the time the technician removed the Frigiking unit for sending it to Buds Benz for overhaul. And, when the overhauled unit was returned from Buds Benz, the power wire now happens to be 10 ga. White, for providing the A/C with 12 VDC primary power. It’s still a mystery why the feed side of the fuse block was Hot at all times, when following the re-installation of the overhauled A/C unit it was powered ON and hot (12 VDC) only when the Ignition key switch was ON. Maybe the conditions cited where the 16 ga. wire overheated from accrued usage while excessive current being was pulled when the A/C was running caused its insulation to melt and possibly short out to an adjacent wire and to conduct 12 volts at all times, even with key OFF. Or, there is possibility that excessive current in this circuit was being pulled through the ignition switch contact and could have been caused by arcing or a short between the 12 volt feed side of the switch to the keyed B+ contact at the ignition switch. Access to the ignition switch area is not possible at this time.
As of today, I have removed the existing fuse block (i.e., the one on the right fender well behind the alternator). I replaced it with two SPST relays, operated by a cabin mounted activation switch. Each relay is activated by a switch on a panel that is secured under the Frigiking A/C distribution box. The A/C Power and Radio 12 VDC power now are now switched by 70A current capacity contacts of the relays. I capped off the previous 12 VDC feed side of the two wires that now have constant 12 Volts. I am feeding the switched relay contact with 12 VDC run direct from the battery. This allows me to activate the radio and A/C independent of the ignition switch KEY ON for radio or A/C power. For the time being I have abandoned pursuit of the reason why the fuse block was powered HOT at all times, even with ignition key switch being OFF. It used to be HOT only when the KEY was ON. That is something I will likely pursue later when I remove the instrument panel for Speedo and Tach cable replacement and dash wood trim replacement.
