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Hazard Switch/Turn Signal System

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I know this is an old post but I have a couple of questions:

 

1. Does the inoperative turn signal flasher prevent the turn signals from lighting up at all?

2. Would no turn signal lights and no dashboard turn signal indicator point to anything in particular?

Edited by Christine

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Christine:

 

To answer your questions:

 

1) yes

2) yes, bad turn signal switch, or bad fuse, bad wire, bad wire connection.

 

First it would nice to know exactly which model and year the automobile is. Typically the 240 and 260 Z's by design had heavy current flowing through the headlight and turn signal light switches. In order to fix the design, heavy current relays need to be installed in the headlight circuit. Then the headlight switch can be allowed to control these relays with a MUCH smaller amount of current and preserve the integrity of the headlight switch. On the 240Z and maybe the 260Z, the left and right headlights receive +12 volts from individual fuses. This inherently is a good design. The headlight switch on the stalk on the steering column switches the low or ground side of the circuit. This is still OK except it switches HEAVY CURRENT which is NOT GOOD.

 

First thing is to trouble shoot the problem to see if +12 volts is getting to the headlights. Once that is determined to be good, move on to the ground or return side of the circuit. Temporarily grounding the return side of one of the headlights and then the headlight lights up says the column stalk switch is defective. These can be either repaired if not extensively damaged or replaced. But after replacement of same install the additional relays through which the heavy current will flow rather than the stalk switch.

 

If there are any further questions, please do not hesitate to ask.

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I have a '79 280z.... Headlights are fine ( you were mentioning headlights in your post), hazards are fine, it's only the turn signals (f/r) are not lighting up or flashing. The lights do operate as they were tested... but I still haven't found the problem.

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Christine, on my '78( which I have to assume is the model you have because 79 was first year for zx model) there are flasher relays that I would check first. If you don't have a blown fuse then the next thing I would check would be for a bad flasher relay. The first time my headlights wouldn't work this was the problem. My turn signals quit working again, but instead of fixing it I just yanked the engine and transmission and entire engine harness and started modifying for a v8.

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OK, if the forward and aft turn signal lights it is likely the turn signal switch or the turn signal flasher. On the 240 and 260Z's there are two flashers, one for turn signals and one for emergency flashers. Not sure of the location of these two but they are likely identical. Find both and swap them if they are identical and see if the problem stays the same or goes to the emergency flasher system. If the latter is true, then replace the flasher for the emergency flasher system. If it remains with the turn signals then it is likely the turn signal switch or wiring. Try there and post the results.

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The 280ZX wiring diagram shows maybe two different types of flashers for turn signal and emergency and therefore may not be swappable. Also the wiring for turn signal may also go through the emergency flasher enable switch. Therefore there are two suspect switches. The turn signal switch and emergency flasher switch. The wiring diagram is complex and not well represented. +12 volts can be checked for at the tail-lights turn signal etc. If +12 volts is not present then there is a bad fuse or wiring or connector.

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Ok thanks for the responses, we did check the switch - my combo switch was definitely bad. I had another switch from a 260, took that switch and soldered the wires where they belong, tested continuity and hooked it up, then tested for voltage. Seems to be good so, flashers will be next to check. I have been down in the "pit" and saw both flashers, the one over the steering column with points to the turn signal flasher, since I can feel/hear the flasher for the hazards when it's on (that one is closer to the front of the dash). I'll bypass the flasher and see if at least they light up.

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Any more progress on the situation?

 

So, We got a chance to take a look again at the issue. I first replaced the flasher, checked the voltage coming in and out, looked fine - 12 volts min.

 

We took apart the hazard switch, tested to make sure power was being supplied to the turn signals when the hazards were switched off, and it is.

 

There's absolutely no power getting to any of the signals when the turn signals are engaged, but there is power when hazards are engaged.

 

My husband checked the combo switch again just to verify what he is seeing....

He saw that the green wire in the middle of the three wires supplying the turn signals has power on it (which it should), but the white/red and white/black are showing as going to ground (always), is that normal?

He tested the combo switch for continuity (when engaging the turn signal) and it looks good.

 

Not sure what else to do other than trace every wire, but to me, the fact that all turn signal lights are not working and the tach light (for the turn signals) is not working, means that something that is common to all them is not right but I could be wrong also. Why is this so complicated? lol

 

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How was the following verified? "There's absolutely no power getting to any of the signals when the turn signals are engaged, but there is power when hazards are engaged."

 

Was a voltmeter used at the bulb socket to verify that +12 volts was present? From the wiring diagram it appears that +12 volts for these lights comes from the fuse panel. It therefore appears that the turn signal switch supplies a ground/return to the other side of the bulb sockets. With all the other lights that are not working it would seem that a ground/return is missing for these. Supply a temporary GOOD ground to the chassis from the switches to see if some lights come on. This assumes the wiring from the bulb socket to the cabin switches are OK. Electrical continuity from the bulb socket to the cabin switches can be checked with a Multi-Meter and long wire to the bulb socket.

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How was the following verified? "There's absolutely no power getting to any of the signals when the turn signals are engaged, but there is power when hazards are engaged."

 

Was a voltmeter used at the bulb socket to verify that +12 volts was present? From the wiring diagram it appears that +12 volts for these lights comes from the fuse panel. It therefore appears that the turn signal switch supplies a ground/return to the other side of the bulb sockets. With all the other lights that are not working it would seem that a ground/return is missing for these. Supply a temporary GOOD ground to the chassis from the switches to see if some lights come on. This assumes the wiring from the bulb socket to the cabin switches are OK. Electrical continuity from the bulb socket to the cabin switches can be checked with a Multi-Meter and long wire to the bulb socket.

 

Yep used a multimeter to check.

 

Based on info we got from several posts here.. Power for the turn signals comes from the fuse box, thru the hazard switch, then thru the flasher, before going into the combo switch wiring. With the hazards off, the hazard switch makes proper contact to complete the circuit to send power down to the flasher, out to the white wire, to the combo switch plug. White turns into green wire on the plug and I do have +12v there.

 

When I engage the turn signal, voltage drops to 0 on that green wire.

 

When the turn signal is in the center position (off) the white/red and white/black wires on the combo switch have 0 volts on them, and testing with a continuity tester, those go to ground.. Could that be a short in the wiring or is that normal?

 

When the hazard switch is turned on, those white/red and white/black wires show +12v on them (flashing obviously). All 4 corners, and the dash indicators light up when the hazard switch is turned on.

 

Will check the ground to make sure that is good. But pretty sure it was ok.

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Christine:

 

I am really trying to think of how to resolve this issue. I must trust what you are telling me is accurate and must be VERY DETAILED. The more detailed the better with MUCH CLARITY. Need to establish a baseline from which to proceed. Next, please disassemble one of the front or rear turn signal lights to get at the bulb socket. With the running lights OFF, check for +12 volts on all three of the bulb contacts. The sleeve and two terminals at the bottom of the socket.

 

In the elder years of the Datsun, the hot side +12 volts was routed from the fuse panel to the bulb. Then the return or ground side was switched on and off. This was the electrical design theme at the time of the 1971 Datsun 240Z that I know for sure as I have one. Not so sure about the 1979 models. That is why I need you to test for same to see if the electrical design theme carried over to the later years. Not so serious as it the reverse of the American Automobile electrical system designs which switch the positive side. Just 6 of one and half-dozen of the other.

 

If Datsun carried through the electrical design theme from older models, then the combo switch needs to assert a ground to the bulbs through the turn signal switch then back through the common turn signal flasher which is nothing more than a normally closed thermal switch that when has sufficient current through it heats up and opens up momentarily then cools down an closes the circuit once more to light the turn signal bulbs.

 

I hope the forgoing has provided some info for you. Look forward to hear from you as to the constant voltage on the turn signal bulbs with the headlights and running lights TURNED OFF.

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I still suspect a faulty flasher unit. Make sure you have the correct type, the stock units for hazards / turn signals aren't interchangeable - I tried a hazard flasher unit on the turn signal circuit and it doesn't work. Out of interest, have you replaced your turn signal bulbs with LEDs? If so then there won't be enough current draw for the turn signal flasher unit to switch on and off; but when the hazards are operating, all the turn signal lamps would be activated and the current draw would probably be enough.

Edited by morbias

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Ok guys problem resolved. The turn signals now work.

 

The problem was in the black connector that sits on the passenger side under the dash closest to the center console.

 

This thread helped also: http://forums.hybrid...-sticky-please/

 

I didn't have to do anything that the thread said except clean the connectors and make sure they had a tight fit. Although they didn't look corroded, I still cleaned them with electronic cleaner and hit it with a little sandpaper. I also closed up the female side connectors a little with a tiny screwdriver so that they made better contact. After that everything worked. Makes sense since I had no power to any of the lights at all, power was getting to the hazard switch, combo switch, flasher but not to signals or tach. I cleaned most of the other connectors under the dash, but I'm going to do the same for ALL of them. I cleaned one headlight connector in the same manner, and that headlight is now brighter then the other, so it definitely makes a difference.

Edited by Christine

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What led you to the black connector on the passenger side?

 

The thread I referred to above in the link above and this post also was a path to follow.

http://forums.hybrid...post__p__560692

 

Since we had already checked everything else, and like I said, power was being supplied everywhere EXCEPT the wires to the signals themselves, something "common" had to be the culprit.

 

Fortunately, that connector is the "common" piece that routed the power to the signals and apparently the tach indicators also.

 

We would have found it next either way, since the next thing to do would have been to trace the wires from the hazard switch to the signals. Every one of those wires goes into this connector and out the other side (and though more connectors) before and after it gets separated to FL/FR/RL/RR.

Edited by Christine

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