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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Fuel pump.

See here:
http://www.bowlsby.net/914/Classic/zTN_Man06.pdf

The empty fuse slot is not used on the later cars. Don't put anything in it.

The dimming lights could indicate bad grounds/connectors but to be affected that much by your brake lights is a little concerning. Going to take some serious troubleshooting to figure that one out.

Measure the voltage at the battery, not the "eye candy" voltmeter.

The Cap'n

Get yourself a Haynes manual. It has wiring diagrams in it.

Or, go here:
http://www.pelicanparts.com/914/914_electrical_diagrams.htm

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

define AAR

Aux Air Regulator. Current is about 1.2 amps.
Tom

Auxiliary Air Regulator. Lets more air into the manifold when the engine is cold, keeping the idle from sagging too low.

--DD

Thanks Krust. Checked the voltage at the battery as you suggested, and it was at 13.8v. Even with the lights on and brakes applied, never changed. Good advice and thank you.

Now, whats up with the gauge? Replace it? Or is there an issue that it sees somewhere down the electrical line that may be a problem?

Your voltmeter is OK. It is reading the voltage drop on the wire coming ffrom the battery. Not the correct way to monitor battery voltage, just the cheapest for the factory. Correct way would be to run a wire from the battery to the voltmeter only.
Ever been in the shower when someone flushed and get burned by the water? Same principal.
Tom