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No Hazards, No Turn Signals when headlights are on


BGB
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New year same topics :) I've searched endlessly... read every Mike Self post ever and am just stumped on how to keep going on this.

 

I have a 1970 build 6 fuse car that I have been trying to get back into safe operation.

 

I have never had working hazards since getting the car. I now after going through all the bulbs, and grounds have functional turn signals (with headlights off), headlights, running lights and high-beams but when the headlight switch is turned on the signals stop functioning. I have voltage at the relay at #49 and #49a in both headlight on and off, I have tried a new flasher relay but the problem persists.

 

My understanding of the circuit is the power comes through the hazard switch. How can I isolate the Hazard switch the see if that is the issue? Where else should I be looking for power in the circuit?

 

Cant wait to drive at night so the wife stops nagging me its not safe to turn the headlights off then activate the turn signal, tun then turn the headlights back on ;) 

 

 

 

 

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That's a new one on me too...On your six fuse car, fuse 4 operates the hazard flashers and is live regardless of whether the ignition is on or off.  Turn signals are on fuse 5, which only functions when the ignition is on.  Your headlights aren't fused at all (!), so the only thing I can think of is the headlights are drawing so much current that they're keeping sufficient power from reaching the flasher to allow it to operate.  That smacks of resistance in the circuit somewhere.  

 

All the auxiliary stuff on the car--short of the starter--takes current from that thick wire that's fastened to the + battery terminal with a 6mm bolt.  Have you removed that bolt to make sure the terminal is nice and clean, the wire isn't frayed at the terminal and the bolt is tight?

 

As I'm sure you know, both the turn signals and hazard lights are powered through the hazard switch, which has two sets of contacts inside--one set is live all the time and powers the hazard lights (through the flasher relay) when the knob is pulled (it's a pull knob on a '70).  The second set is live only when the ignition is on, and then allows current to flow to the turn signal lever whether the hazard switch is on or off.   Those knob switches are a lot more reliable that the later pushbuttons used from '71 on.

 

The fact that both flashers and turn signals work with the headlights off tells me that both switches (turn signal and hazard) are OK, as is the flasher relay.  So...unless I'm missing something important, I'm guessing those headlights are drawing current through some resistance somewhere and keeping that transistorized flasher from doing its duty...

 

That's all I've got...

 

mike

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10 minutes ago, Mike Self said:

That's a new one on me too...On your six fuse car, fuse 4 operates the hazard flashers and is live regardless of whether the ignition is on or off.  Turn signals are on fuse 5, which only functions when the ignition is on.  Your headlights aren't fused at all (!), so the only thing I can think of is the headlights are drawing so much current that they're keeping sufficient power from reaching the flasher to allow it to operate.  That smacks of resistance in the circuit somewhere.  

 

All the auxiliary stuff on the car--short of the starter--takes current from that thick wire that's fastened to the + battery terminal with a 6mm bolt.  Have you removed that bolt to make sure the terminal is nice and clean, the wire isn't frayed at the terminal and the bolt is tight?

 

As I'm sure you know, both the turn signals and hazard lights are powered through the hazard switch, which has two sets of contacts inside--one set is live all the time and powers the hazard lights (through the flasher relay) when the knob is pulled (it's a pull knob on a '70).  The second set is live only when the ignition is on, and then allows current to flow to the turn signal lever whether the hazard switch is on or off.   Those knob switches are a lot more reliable that the later pushbuttons used from '71 on.

 

The fact that both flashers and turn signals work with the headlights off tells me that both switches (turn signal and hazard) are OK, as is the flasher relay.  So...unless I'm missing something important, I'm guessing those headlights are drawing current through some resistance somewhere and keeping that transistorized flasher from doing its duty...

 

That's all I've got...

 

mike

I will check the connections at the battery tomorrow. Your comment on auxiliary loads/draws is interesting. At some point in time a stereo was installed and the wiring is pretty nutso with lots of wires going directly to the battery, might be worth just disconnecting them all and then check the light functions

 

Is their any way to test the hazard switch? Can I jump the terminals to determine if it’s even good? The hazards do not work in any situation and right now its hard for me to tell if the switch is even at fault 

 
 
 
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10 hours ago, BGB said:

Is their any way to test the hazard switch? Can I jump the terminals to determine if it’s even good? The hazards do not work in any situation and right now its hard for me to tell if the switch is even at fault 

If the turn signals work properly (not including the headlight problem) then the flasher relay itself is OK, as the hazards use the same flasher relay.  So the problem is either in the feed to the flasher switch, or the switch itself.  Here's how to check.

 

First, make sure fuse 4 is good and clean; if you have power at the cigarette lighter and the interior lights, it's good as they share the fuse with the hazard flashers. Next...

 

You'll have to remove the hazard switch from the dash in order to see the terminal numbers on the switch's backside.  The red wire that leads to terminal 30 is the hot lead for the hazard flashers, and comes from fuse 4.  It should show +12v at all times.  If you have 12 volts at terminal 30, next use your ohmmeter to make sure that the brown wire is actually going to ground.  If either aren't doing their duty then the problem is in your wiring. 

 

If you have voltage and ground as above, turn the switch on and check voltage at the terminals marked L & R.  Those are the feeds (through your flasher relay) to the left and right turn signal bulbs when the hazard flashers are working.  And a tiny bulb inside the switch knob itself   should blink in time with the hazard flashers, as well as the dash light.  If you have no voltage at terminals L&R (it'll be intermittent as the bulbs flash), then the fault is probably in the switch.  Only way to tell is to try another switch.  They don't go bad very often, so someone on the FAQ is bound to have one.  Unlike the later switches, they can't be taken apart and repaired.  

 

Let us know whatcha find...

 

mike

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So no power at terminal 30. I have continuity at the ground wire to the body. Looks like I am gonna have to start pulling wires and cleaning up the mess of previous repairs for real now. I spent the afternoon cleaning up a ton of the wires near the battery and found quite a few poor soldering repairs, strange splicing and way to many Red wires 😕 My guess after studying the wiring diagram is the Solder point (#10 location) has been removed and all these wires are running straight to the positive terminal.

 

 

After the fuse box according to my wiring diagram the Red wire bringing power into the Hazard Switch goes to location #32 which is a solder point. Where in the car is this located?

 

Also I see "Test Equipment Connection" at location #11 what is this? 

 

Unfortunately I may have to pause on this until next weekend when I have more time to sit down and devote to this

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Sounds like a real hack worked on your wiring. I think Mike is correct about the headlights pulling too many amps. I would first suggest removing all non original electrical equipment and wiring, that includes radio which was a dealer installed option. Next you should check and clean all of your grounding points. I would also suggest checking your alternator output voltage and battery. The hazard switch is probably the problem. The early style ones were not a very good design, which is why they replaced them.

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