Hi, I have a 1973 240z where the wiper fuse keeps blowing. It used to work fine before I put a higher output alternator in. The original power wire is hooked up to the alternator terminal. I also have a 6 gauge wire going from this alternator terminal to a bus bar (terminal where all accessories get power) and from the bus bar to the battery. Where should I check for shorts? Did my wiring job mess something up?

Thanks for any help.

How slow was the wiper motor Before the alternator swap? I ask because they get slower and slower and will pop fuses due to the motor being too hard to rotate. Maybe taking a day and pulling the wiper motor and rebuilding it (cleaning, blowing it out and regreasing) might do you and the fuse some good.

Resistance is a big issue in the 240Z's, as well as all S30 Z's. As a sidenote, clean all your connections and terminals. Seriously, Take a day to open each and every connection you can get your hands on and clean them. Some people use DeoxIT-D5.

Look it up, it's a great contact and connector cleaner (slime, oxidation, char, etc)

Grounds are another trouble spot. Pull and clean all associated Ground points. One below the battery on the frame. Run better or bigger power wires and keep the battery terminals and posts clean and coated with a Battery terminal coating (protectant)

Dave

I will try to do this soon. After replacing the fuse once, I flipped the switch, the wiper motor buzzed for a split second and I heard the fuse pop.

Would this be indicative of too much resistance on the motor?

Thanks!

I'd examine the wiper pivots first before undertaking revamping the wire harness.

The motor is getting resistance from the wiper pivots and linkages, which added to the corrosion on the wires both act together to overload the fuse.

Simply removing the wiper motor and the linkages will allow you to disconnect and reconnect the motor's connection which combined with a mechanical pivot cleaning may be all you need.

FWIW

E

That's kinda what it sounds like. I would just pull it and attempt to clean and regrease it, then pull the wiper linkage as well and clean and regrease that as well. If the damage is not too extensive. The rotating shafts (on the wiper arms at the cowl panel) wear out due to bad bronze bushings. Clean and lube as best you can.

Wear and tear, resistance, old parts and lack of grease are the big issues in the wiper system.

Dave

Regarding the DeOxit treatment, DeOxit D-100 is the best stuff to use at first. D-100 will literally 'melt' the corrosion off electrical contacts. DeOxit D-5 is more of a maintenance product that you should use on your connections annually.