When i did my restoration project on my 73Z I purchased a rebuilt turn signal switch from datsun universe. It worked great for about a year. The other day I started having problems with the turn signal on the left side. It would not lock in or illuminate. Everything on the right side worked fine. After checking all the obvious potential culprits, I contacted datsun universe and he told me to send it in and he'd check it out. Below is his response as to what he found and a potential long-term fix. My question is: does anyone know who may sell this modification or how to fabricate one. By the way, the guy at datsun universe is a great guy, very helpful, and fast turn around. I also bought a reconditioned headlight switch from him as well. He does all the rebuilding himself.

Datsun Universe reply to me.....

"Hello Paul, the attached picture illustrates what your switch issue is; too much voltage coursing through the switch and fouling the contacts. This is a normal issue for a 240z. When I measured continuity on the left side turn signal switch it fluctuated between 35.xx ohms and 65.xx ohms. Anything over .19 ohms is going to start causing problems for switch operation.

I knew I was going to find something like this when I opened the turn signal switch up. The long term solution for this issue is to invest in a 240z aftermarket plug and play turn signal relay harness. It only sends something like 2 amps through the switch as opposed to the 13 or so that comes from the stock direct battery hook up.

I cleaned the contacts and changed the spring plate and turn signal switch housing and the freshly painted turn signal lever will dry overnight.. You have a good switch here;

The turn signal geometry and parts thereof are good, the stroke of the turn signal lever is good. the lever locks in place like is supposed to, the switch return function still works etc.

I would invest in that relay harness or learn to clean the contacts yourself ( s30 ZCAR switches are made to disassemble for maintenance) as my switch warranty is voided by vehicle electrical causing switch damage so that is the end of my commitment concerning repair of your switch".

Any help would be greatly appreciated.

I haven't seen much about turn signal contact pitting in my time browsing the Z car WWW. The headlight and running lights have a problem for sure, melting/breaking solder joints and burning contacts in the switch, but a turn signal switch problem I've not seen.

But, the cure for the headlight and running lights problem is a relay so if your switch works and you want to avoid the problem in the future a relay would be a good idea. I haven't looked at a 73 wiring diagram closely but I'd think a relay in front of the flasher should get it done.

I tried to take a look at the wiring diagram in the 73 FSM but, wow, it's hard to look at. Can't tell which side is the power supply side but a meter would solve that problem.

On the other hand though, what datsun universe seems to be saying is that your turn signal lights were pulling too much current, causing the contacts to pit and overheat. Somebody handy with a meter might be able to test the possibility. If you did have a high voltage problem it would manifest in many other places also, so "high voltage" doesn't really make sense.

In short, your problem is kind of unusual. Hope my thoughts help a little bit.

Edited Friday at 04:21 AM2 days by Zed Head

Per the recommendations from @Zed Head , here are two excellent upgrades you can make to improve your lighting situation:

Headlight relay kit: https://www.thezstore.com/product/3861/headlight-relay-upgrade-harness-70-73-240z

Parking light relay kit: https://www.thezstore.com/product/5031/parking-light-upgrade-harness-70-73-240z

Take note of the fitment limitation regarding the Parking Light kit for the '73 240Z.

Another improvement you can make is to switch out all of your small exterior bulbs to 3W LEDs. This would be front parking and turn signal, sidemarkers, rear tail light and brake, license. If you do so, rememebr to use LEDs that are the same color as the lens cover. If making this change for the turn signals, you will also need to swtich the OE flasher cans for the turn signals and hazard switch to aftermarket electro/mechanical units, a easy plug-and-play change.

Your turn signal issues are possibly caused by the heat from high resistance in your wiring circuits: corroded bulb sockets, fouled terminals in the wiring, damage at the fuse block (check the underside), damaged wiring.

Hope some of this helps.

15 hours ago, z3beemer said:

When i did my restoration project on my 73Z I purchased a rebuilt turn signal switch from datsun universe. It worked great for about a year. The other day I started having problems with the turn signal on the left side. It would not lock in or illuminate. Everything on the right side worked fine. After checking all the obvious potential culprits, I contacted datsun universe and he told me to send it in and he'd check it out. Below is his response as to what he found and a potential long-term fix. My question is: does anyone know who may sell this modification or how to fabricate one. By the way, the guy at datsun universe is a great guy, very helpful, and fast turn around. I also bought a reconditioned headlight switch from him as well. He does all the rebuilding himself.

Datsun Universe reply to me.....

"Hello Paul, the attached picture illustrates what your switch issue is; too much voltage coursing through the switch and fouling the contacts. This is a normal issue for a 240z. When I measured continuity on the left side turn signal switch it fluctuated between 35.xx ohms and 65.xx ohms. Anything over .19 ohms is going to start causing problems for switch operation.

I knew I was going to find something like this when I opened the turn signal switch up. The long term solution for this issue is to invest in a 240z aftermarket plug and play turn signal relay harness. It only sends something like 2 amps through the switch as opposed to the 13 or so that comes from the stock direct battery hook up.

I cleaned the contacts and changed the spring plate and turn signal switch housing and the freshly painted turn signal lever will dry overnight.. You have a good switch here;

The turn signal geometry and parts thereof are good, the stroke of the turn signal lever is good. the lever locks in place like is supposed to, the switch return function still works etc.

I would invest in that relay harness or learn to clean the contacts yourself ( s30 ZCAR switches are made to disassemble for maintenance) as my switch warranty is voided by vehicle electrical causing switch damage so that is the end of my commitment concerning repair of your switch".

Any help would be greatly appreciated.

There's some BS going on here. 13Ax14V=182W. I'm not sure whose backside produced a 13A figure. There are 2 (two/dos/zwei) 23W bulbs and a 3W bulb (on the gauge) in the circuit.

Please invite the person who gave you that response to come here and show the testing.

Until proved otherwise, I posit that someone is covering up for shoddy work. I am interested if someone can make me eat my words.

I'll see if I can set up my scope with ammeter to look for transients that even come close to 13A

Electrical principles can be difficult. datsununiverse might be more of a mechanical person. If he cleaned up the switch and rerturned it that seems fair. Sounds like he's saying that he doesn't really know what went wrong. People often get voltage and current mixed up.

I found his eBay store front but don't see a web site. Can't tell what "rebuilt" means.

https://www.ebay.com/str/datsuniverse

I found a "restored" listing.

https://ebay.us/m/4gvALW

Sounds like he's from the Al Allen school of parts restoration.

So, can we think up some simple tests to run, maybe at the flasher or the plug itself, that might show low resistance through the turn signal circuit? Or high resistance at the contacts.

Any chance the flasher itself is pulling too much current?

Or do we just assume that the cleaning and modification was not well done?

Seems like the sliding contacts must have got gummed up.

20 hours ago, z3beemer said:

g problems with the turn signal on the left side. It would not lock in or illuminate. Everything on the right side worked fine.

This is actually datsuniverse writing -

20 hours ago, z3beemer said:

When I measured continuity on the left side turn signal switch it fluctuated between 35.xx ohms and 65.xx ohms.

Daniel Parsignault is Datsuniverse and he's been an eBay player for a long time.

I have sold him things and have bought a few things. I liken him California Datsun for "rebuilt parts" That is just my opinion of course.

@jfa.series1 can fix you up…..right Jim? Can’t understand why these things don’t work properly….they’re only 54 years old.

7 hours ago, Diseazd said:

@jfa.series1 can fix you up…..right Jim? Can’t understand why these things don’t work properly….they’re only 54 years old.

I'm older than that and I still work properly! Sometimes...Sort of...;)

9 hours ago, Diseazd said:

@jfa.series1 can fix you up…..right Jim? Can’t understand why these things don’t work properly….they’re only 54 years old.

Thanks Guy, but I am disinclined to follow someone else's work in this case. In his ebay post I noted that he "modified" plastic connectors and the metal base. With all of the switches I have refurbed I have not yet found a need to modify the OE components - sometimes replaced with new or from the parts bin but never modified.