Electrical problem after problem after...

[Seanh]

I'm haveing so much trouble with the electrical in my Datsun since winter has started...First off, the other day, I had my left turn signal on, and was going thru a corner when I heard a loud pop and the car began running like crap. So I stopped, checked my fuse in the engine compartment from the starter to the alt, and it was blown. Replaced it, and drove home...took dash apart, and found the source of my short and repaired it. Well, my turn signal doesn't work anymore...right one works fine, but the left just doesn't come on at all. The dash light for it comes on dimly, but doesn't blink and the outside light for it doesn't come on at all. Whats going on here? Flasher burned out?

Now, my brake lights are out a couple nights later, both of them. I'm thinking its the switch by the brake pedal, how do I check it?

Also, now last night when I get in and start my car, no heat! Blower motor is not turning on. So, I check the wireing behind the panel, and its plugged in good and everything. Any other ideas? I don't know where something could have gone wrong here...

Another one...When my car is idleing in the driveway, no electric fan, heater, headlights, or stereo system on, the voltage at the battery is approx. 15.5 volts. When I flip the headlights and electric fan on, it drops to 12.4 volts. Shouldn't the alt. keep it at like 14.4 all the time? My alt. looks brand new (perhaps by last owner, but not sure,) and my battery is also brand new since I'v got the car I replaced it myself. What could be the problems here? Bad alt., voltage regulator maybe? Any tests I can do to determine?

And last off, this isn't a problem, but something I just want to do. I'm going to replace all the wireing on the datsun sometime soon. I'm going to run all new wiring into the cabin from the engine bay, and all new fuse panel, and most everything. I'm wanting to know what I need to do. From the looks of the stock setup there is a wire from the batt. to the starter, and then the starter to the alt. Which I think is stupid, so when I re-do I'm going to run a wire from the battery to the alternator directly, seems more logical to me. Then I'm going to change it so that the heavy gauge wire going into the cabin comes from the battery also, not the alternator as is on my current setup. I'm going to relocate the fuse block also, to under the passenger side part of the dash, just for my own reasons. I'm assuming that the wire comming into the cabin from the alt. only goes to the fuse box correct? And is then distributed from there? If not, where else does it go that I might not find? I know this is a lot of work, but I'm going to completly re-do this car in the future, so I might as well start here since I love working with electronics.

Thanks!

[sjcurtis]

Sean,I have sympathy for you and the electrical problems in your car. From what you have said it looks just like the normal Z seasonal problems that I have with mine. I find with my Z the indicators , wiper and washer , heater fan power and even EFI fuel pump system and low/high beam will play up occasionally with the change of season or storage time.

I did worry and expect the worse like you are right now. The up side is if you can except that you need to make minor changes, fuses an fuseable links, and ocasionally clean the contacts at a lamp or a plug then you will probably find in the long term the wiring loom in your z is still good and maintainable. I have been enduring these season change irratations for the last ten years so now I know when I hit the ignition and I dont here the EFI pump running, I pull the fuse and re fitt it then it runs normally again. This function normally works for all the systems I have mentioned except the beam lights, I know if I do not get low beam when I select it a bump on the road will initiate the change shortly after selection, same for high beam. The lights are due to a relay sticking. I use the high lowbeam circuit in the Z wiring to initiate only all light power comes through the relays for high/low beam. So Sean you are not alone, good luck.

Steve :classic:

[zoom240]

I can't respond to most of your questions, but I've been plagued with electrical problems too.

The sagging voltage disappeared after I replaced the alternator AND voltage regulator.

I replaced my turn signal switch & headlight switch. The turn signal problem was likely poor connetcions in the plastic plugs leading to the fuse box as the new turn signal didn't fix the problem. I eventually tracked it down to one of the plastic plugs that connect up to the lines leading through the firewall (that mess of stuff under the passenger side).

I'd be interested in rewiring stories, as this gets old... I prefer to tinker with the engine & I don't like tracing down ground problems.

[EScanlon]

First off:

If you are NOT familiar with automotive wiring, DO NOT go modifying the circuitry (wires). That 10 gage "wire" from the battery to the starter is in fact a fusible link and not a true "wire".

There are various wires that may seem redundant, not needed, superfluous and even stupid in the 240 but you will find that the system can in fact be made to work properly. My car has the original wiring and I've incorporated fog lamps, courtesy lamps, newer h4 halo headlights to mention a few items.

I would suggest that you first look at your fuse box. Take it out, clean the contacts for the fuses, replace fuses if they fail a visual and / or a physical continuity check. Don't assume that if they "look" good they are. It is MUCH cheaper to replace all of the fuses than to repair a burnt wiring harness or car.

Next, since you've already experienced problems, check your combination switch. Don't just wiggle the thing, check for continuity and if necessary, replace it or repair it.

That you have turn signals on one side says the flasher is good, the side they're bad on is probably suffering from a bad contact either in the combo switch, or a short in the wiring.

There's tons of information in the archives, just search for wiring or fuse box or any one of half a dozen words and you'll get a ton of information.

If you are planning on rewiring the car, go to the boneyard and get a wiring harness from the same year if possible, as there are some changes from year to year. Also, make sure that if you have a manual you get one from a manual car (ditto automatic). Then replace it after labeling each connector on BOTH sides of the connection. If you don't do this, you'll make this into a major PITA job.

Feel free to e-mail me or post here as I've done a complete dash rewire as well as getting items to work that others have had problems with.

Enrique Scanlon

[sjcurtis]

Good response Enrique, excellent imput. You mentioned courtesy lights, I take it you have utilised the footwell lighting wiring loops in your car and these lights come on with the rear dome light, when the door opens. well thats what my courtesy lamps do.

No burnt wires please.

Steve :classic:

[Daniel]

EScanlon is indeed correct about the rewiring from factory.Some things may appear incorrect but believe me those guys at datsun have forgotten more than we will ever know about wiring a car.Also by doing your own thing it makes the standard wiring diagram invalid.Therefore lots of trouble to track down problems in the future.The battery issue with lights on is correct.The alt. doesn't even kick at that low idle rpm.Your turn signal could be a bad bulb.Unless they all work,it won't flash.I think checking the combo switch and turn signal switch is a great idea.The fan motor is easy enough to test.Check for voltage at the fan,if yes,take it out and see if it will spin by hand.If yes apply 12v from an external source like a battery charger and see if it moves.As for your brake lights,checking the switch is easy.Look at the brake pedal arm and you'll see it.Its just a momentary contact switch.Check across it with your continuity meter once you've unhooked it from the circuit.Odds are its good.The brake lights also run thru the combo switch.Check the factory wiring diagram to see that.HMMMM There is something to being standard huh????Sorry,I had to say that:cry: Daniel

[Gav240z]

Now this is only a suggestion but I owned a 75 260z that had been fitted with an electrical fan and I believe the fan alone is a cause for electrical problems.

The installation was not done by me but by the previous owner and the car gave me nothing but trouble. It fried 3 alternators and killed 1 battery.

Turn signals are usually just the globes on one side they all need to be good. If not it's usually the flasher unit located under the dash.

All old cars are going to have electrical problems as the electronics technology back then was not as accurate as todays. Also ageing parts doesn't help.

My 240z has stock wiring but it has undergone some upgrages. The electronic iginition is a start. No ballast resistor. The H4 Hella headlights work nicely. The flasher unit is a more modern one works fine. The rest as far as I can tell is all stock and it's working fine.

My suggestion give the electric fan the flick the HP is saves isn't worth it plus the clutch fan makes the car more reliable.

[Seanh]

Alright, well my stock clutch fan was shot to peices, so I replaced it with an electric one I had laying around. It only pulls 9 to 11 amps, so I don't see why that would fry an alternator. My battery is a 950 cca, brand new. Also, the wire between the alternator and starter on my car IS simply a wire with a fuse holder spliced into it. I burn it so much that I am sick of the hassel of replacing fuseable links, I hate them with a passion. Also, theres not much to my fuse box. Most of it is burnt up or busted, and I can practially take all the fuses out and the car will still run just as it did before, the majority are not even hooked up on the bottem of the panel, from the pervious owner (not me). I changed my car over to a push button ignition system, and I used that little panel that covers the fuse box as my switch panel, so I'd like to free up some space under there, so thats why I want to move my fuse box, and also convert it to a blade type box. I'm not going to mess with another stock wireing harness, with my knowledge of electrical work it would just be easier to do it myself. I'm only going to be reaplaceing the main power wire going into the cabin to the fuse box, and then from the fuse box out...I'm going to take my alternator out and have it rebuilt it looks like...since I'm doing that I might as well have them bump up the amp output on it as much as I can afford.

[billcapp]

Just a note about the electric fan...make sure the power to the fan is run through a relay from the battery. The relay solves alot of electrical problems.

[EScanlon]

At this point you really leave us hurting for information. Once you modify the system from what the wiring schematics show, and what the car came with, we then would need to be there or be psychic before we could be of good help.

If on the other hand you would like to return the system to stock, you'd be surprised at how much trouble you could eliminate. But with all the wiring and switching you've added / changed, this might not be what you want to do.

Some of the mods you've done can be done with the stock harness and very little alteration of the harness. The electronic distributor, removing the ballast resistor, H4 headlights, Electric fans are all items that have been done and documented sufficiently so that people can assist you in getting it done. It's when someone does something completely "logical" or "obvious" that we must find out what that person was thinking.

For example, the fact that your fusible link was failing often are prime indications of a major problem. Replacing the fusible link with a fuse, and no doubt a higher amperage fuse is like putting a rag instead of a gas cap on a gas tank. At that point you are literally driving a Molotov Cocktail waiting for a match. Same thing with the electrical, it blows the fusible link, so you replaced it with a fuse. If they had been of the same amperage, then the fuse would be the one to be blowing continuously now, as the main difference between a fuse and a fusible link is that one is a fast blow and the other is a slow blow. The fusible link "forgives" short duration excesses in current, whereas a fuse will not.

I hope you don't feel that I'm putting down what you've done. I'm not, I'm just pointing out that if you hook yours up in a haphazard or non-standard way you really limit the help we can give you on this site.

2¢

[Seanh]

My fuse is only a 30 amp, which I thought to be a little small in my mind, for the application. My fan is on a switch, to trigger a 30 amp relay, which is tied into the white/red power wire comming into the cabin from the alt/battery. Thing that happened was this: Car was just fine, running with all this stuff. One day I accidently left my lights on, and ran the battery down. So I changed it up for a while, to the point where the car would start continuosly, and took off driveing that night. Well, my amp meter would nearly peg itself when I was on the gas and engine was spinning fast, but would die down when I'm at idle. So I figured this was just the alt. trying to chage the battery (until I relized how the system worked and seeing as it would have nothing to do with the charge rate), then one day the car just died and the amp meter filled with smoke and the fuse link your talking about burnt in half. I was stuck in the parking lot with nothing to do, so I purchased an inline fuse holder and put that in, and boom, worked with with a 30 amp fuse. Never blew again until the other day when I took that corner. I can't find any shorts anywhere, but I'm obviously dealing with something that isn't shorting out all the time, just when the car moves a certain way. However, all this started the day I left my headlights on and ran the battery dead (also replaced the battery at this same time btw)

[EScanlon]

It sounds as though you might have burnt out your regulator. That's either mounted on the fender all the way up front by the radiator and below the fuel filter, OR it's an internal one on your alternator.

I understand what you mean as far as emergency repairs in order to get you going, but you need to look at the cause of the problem in order to avoid further problems.

Trust me on this one, there have been so many posts here and at other websites all complaining about the electrical system on the 240. Many begin with "I blew a fuse the other day...." others begin with "My xxxx stopped working...." or, like yours, "The battery died and I recharged and now......".

All I'm trying to say, is that if you know where and what to do to the system, it will work fine. It's when you start doing the "just what it needs to get running again" that many items get bypassed or shorted and MORE problems begin happening.

I'm sure others will chime in on this.

Take the time one weekend to, if necessary, remove the dash, and check all of the wiring back there against a schematic. You may find that intermittent short and save yourself a bunch of worry. Don't forget the regulator though.

2¢