Engine Compartment Fuse/Relay Help! Options

[914Bryan]

74 914 2.0

Pictured is the relay board in the engine compartment on the drivers side. The pencil is pointing to a blue 25a fuse. That location is towards the back of the vehicle. The open slot next to it has no fuse. What does that operate and what amp fuse belongs there? I dont want to throw a 25a in if that is wrong. HELP,HELP,HELP!!

Also, I am having problems with the drivers side running lights, front and rear are not operational and there is a huge voltage drop when I apply the breaks; goes from 13 to 10. Same thing applies when I turn on the lights. Break lights work and turn indicators work. Im thinking this is all related...Any ideas??

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[Tom]

The front fuse on the relay panel is for the Sportamatic. Not used on other models of the 914. Just a convenient place for a spare fuse. Unless you have a rear window defroster, you really don't need a 25 amp fuse in the rear location. I use an 8 amp as I have no heater blower and it is just fine. A 16 amp would be a back-up if you have that fuse blowing with an 8 and you have the heater blower hooked up and operational.
The AAR is powered with the power thru that fuse and the wire for the AAR can only handle about 10 amps without burning. Several cars have had the AAR short out and damage the wiring harness between the relay board 12 pin connector and the AAR. So the wire for the AAR is "protected" by a fuse that will allow the wire to melt before blowing that 25 amp fuse.
As mentioned before, if you have a large voltage drop when applying the brakes, you have some bad connections somewhere and you need to find and correct them. Where the bulbs go for the brake lights would be a good place to look for corrosion, which can cause extra load for the brake light circuit.
Tom