Electrical Short and Fuel Guage Problems

[lildrip049]

Have a 1968-69 datsun roadster. IO say this because the registration is for a 69 however the wiring diagram for the car is 1968. I have 2 problems. I had the master cyclinder rebuilt by a local mechanic and when I went to pick up the car the fuel gauge did not work and the bottom 20 amp fuse was blown where after testing I have no left or right signal lights. Replaced the fuse several times and the fuse blows, even when I disconnect the 2 flashers. I believe I have the correct wiring diagram for my car. Can someone help guide me in the process of finding this short and fixing the fuel guage..I grounded the sending unit for fuel and the guage did not move. I am thinking of fixing the short first then attacking the fuel guage. Following the wire diagram is difficult so I am looking for alot of assistance THX ,a fustrated Russ

[jrusso07]

Is the 20 Amp fuse that blows the Flasher fuse? There are two flashers, the turn signal and the hazard. Does the hazard flasher work (the pull switch next to the radio)?

In looking at the schematic, the 20 amp fuse that blows (I am guessing at which one) also feeds the horn relay. Does horn work? If not, check the connections to the relay which is under the hood on the inside driver side fender - close to master cylinder. My guess is that the mechanic may have disconnected a wire or replaced a wire on the wrong terminal.

Run down these things

1) Horn works? If not Check for proper connections to relay.
2) Hazard Flasher works? A lot of connections go thru the hazard switch, difficult to troubleshoot sometimes but let us know if the hazards work
3) Check the connections on the stop light switch behind the brake pedal - this doesnt go to ground except thru the stop lights on the rear
4) Does the brake light on the dash light when you pull the brake light switch next to the radio?
5) Last, check connections to the turn signal switch

[Curtis]

He changed your master cylinder, first thing I would check is if screwed up or around with the connectors under the master.

[Curtis]

So the bottom fuse on the 68 feeds the reverse wires. This makes me think if the fuse is blown he did screw up something there under the master. There are two red with black stripe wires, I would check them.

Gauge drawing.
http://www.kendo-usa.org/datsun/datsun_ ... out_68.pdf

Fuse box 68
http://www.kendo-usa.org/datsun/68%20fusebox.pdf

[redroadster]

A 10 amp circuit breaker wired toired/ aligator. clips instead of blowing fuses is a good 1st step. Then look for accessories that do not work off that corcuit investigate those ...you can usualy see them work lite etc before it blows check for grounded pos wires
A short detector can wprk on these few wires cars too