Datsun 620 Pickup electrical questions

MariaAZ · #1 04/11/08, 10:33 PM

DH "surprised" me with a '73 Datsun 620 pickup this morning. It seems to run fine, but it has a couple problems that need urgent tending to.

1) A previous owner installed an aftermarket ignition system. He also installed a push button ignition that is wired from the battery to the starter, but the button has been removed (not the switch but the button itself.) The only way to start the truck is to turn the key in the ignition and bridge the posts on the starter. I'm thinking this might be a miswiring problem that has to do with the button, but I'm not very good with electrical. Any ideas?

2) The same previous owner replaced the stock lights with a newer style. The guy DH bought the truck from said there must be a short somewhere because it will pop fuses if the headlights are on more than a few hours. Where do I start troubleshooting this problem?

danb98577 · #2 04/12/08, 08:35 AM

On #1: You could just go to NAPA and get a new starter switch in the same style this guy installed-just get a heavy duty one. But it would be just as simple overall to buy the electrical portion of the ignition switch and put the system back the way it is supposed to be. On an old 620 I can't imagine it would cost much. You could even switch over to a universal ignition switch-I gather he drilled a hole for the pushbutton switch?
#2: Get rid of those aftermarket boy racer headlamps if you can-should be able to put original sealed beams in existing holders unless he did something weird.. Failing that, install a relay in the headlamp circuit. There are relays available for high power driving/fog lamps that are readily available at parts stores-just follow the instructions that come with it. The lights that are on there now are likely way too powerful for the existing fuses to handle-and don't try to put a higher rate fuse in-that will make matters worse. I see this often as kids try to emulate boy racer types by installing "cool" headlamps/tail lamps-and wind up frying fuses/wiring/switches.

MariaAZ · #3 04/13/08, 03:51 AM

Thanks! The headlights will have to stay awhile, as the PO had fabricated an entirely new front grill/headlight assembly so we will have to locate an original part. I have a feeling the relay might be a more cost-efficient option at this time.

As for the ignition, it looks like the starter is miswired. There are two bolts and a metal blade on it. One bolt is empty, with no wires going to it. The other bolt has a battery cable going to it as well as a heavy wire from the wiring harness. The metal blade is connected to the starter button. There is a wire from the harness that has a matching blade. In checking the service manual, it appears this wire is color-coded to the ignition system so we disconnected the starter button & connected this wire. Nothing happened. I'm beginning to think the starter button was added because there is an overall problem with the ignition wiring. This would explain the new ignition switch. The PO from whom DH bought the vehicle said the starter button worked when he first bought the truck, so I think for the short run we might just replace the button so we can use the vehicle and I'll just have to learn more auto electric

danb98577 · #4 04/13/08, 07:51 AM

Yes, the relay is way to go in this case. The starter-check the library for a shop manual with a wiring diagram-xerox the pages needed and go from there. Some libraries even carry wiring diagram books that are nothing but that. Reference only, but the copy machine will become your pal...I often find shop manuals at yard/garage sales. good luck.