Turn indicator & brake light continuous flashing, Started with a bad bulb Options

[bzettner]

'73 1.7, driving along (IMG:style_emoticons/default/driving.gif) both dash turn indicator lights and brake light started flashing continuously (IMG:style_emoticons/default/WTF.gif) . Found out I had a burned out turn signal bulb. Did my 914World searching and learned the flashing is to "let you know" you have a bulb out, great! Changed out the bulb, flashing continues. Cleaned light socket contacts, bulb ends, changed out bulbs in matched pairs, replaced flasher unit with new RockAuto unit, still continual flashing. Added a little brake fluid, no change.

All my lights work as designed, all of them. Dash turn indicators are bright and work individually when used. The new flasher unit causes the dash indicators to flash continually dimmer than the original unit.

I have found a white w green strip wire near the flasher unit that has no connection, no fitting, just a blunt cut wire with no obvious "answer" to its placement. I am NOT a great schematic guy (IMG:style_emoticons/default/headbang.gif) . Something changed! Ideas?

[bzettner]

Update, I dug and found the other end of the white w green wire, connected and the flashing brake light stops (works like its supposed to) The wiring diagram shows that wire going from the light switch to the speedo. I certainly don't see it going into the back of the speedo. Not sure where it ends up as it nestled well in the dash harness.

Still have the continuous flashing turn indicators in the dash. Everything works as it should except the flashing indicators.

@spoke

[Spoke]

When you say the turn signal indicators flash continuously is this with the key on and no turn signals on? Both flash?

[bzettner]

When you say the turn signal indicators flash continuously is this with the key on and no turn signals on? Both flash?

Yes, start the car, shut the door, release the E-brake (stops the red flashing brake light) and the dash turn signal indicator lights both blink at the same time, continuously. If you put on the right or left blinker, they work like they should until the blinker is turned off.

Besides this, all lights, flashers, turn signals brake light, tail lights, hi/lo headlights and aftermarket fog lights all work as they have since 2013 when I got this car.

[Spoke]

Update, I dug and found the other end of the white w green wire, connected and the flashing brake light stops (works like its supposed to)

The brake light you talked about is the indicator in the multiple gauge correct? Was this wire broken or cut on purpose?

[Spoke]

When you say the turn signal indicators flash continuously is this with the key on and no turn signals on? Both flash?

Yes, start the car, shut the door, release the E-brake (stops the red flashing brake light) and the dash turn signal indicator lights both blink at the same time, continuously. If you put on the right or left blinker, they work like they should until the blinker is turned off.

Besides this, all lights, flashers, turn signals brake light, tail lights, hi/lo headlights and aftermarket fog lights all work as they have since 2013 when I got this car.

It is strange that the turnsignal indicators flash since there's a 2nd relay in the flasher to detect heavy exterior bulb current to power the indicators on pin K on the flasher.

The flasher should only operate when there's a load on terminal 49a. In the diagram, the only paths to ground are the 4-way switch, turnsignal switch or brake warning indicator.

One test is to remove the wires on the master cylinder warning switch under the car and the ebrake wires. Something is creating a load or leakage on terminal 49a.

If the new flasher didn't solve the issue then the original flasher should be ok and should be reinstalled. While the flasher is out, measure the resistance from the plug terminal 49a to ground. It should be infinite since every path to ground goes through a switch thus should be an open circuit.

[Spoke]

'73 1.7, driving along (IMG:style_emoticons/default/driving.gif) both dash turn indicator lights and brake light started flashing continuously (IMG:style_emoticons/default/WTF.gif) . Found out I had a burned out turn signal bulb. Did my 914World searching and learned the flashing is to "let you know" you have a bulb out, great!

The most classic flashers (not the 914) alert the driver of a burned out bulb by hyperflashing at 2x the normal 1 flash/second rate only when the Left or Right turnsignal is selected. The 914 flasher alerts the driver of a burned exterior bulb by flashing both turnsignal indicators together when the L or R turnsignal is active.


The flasher should never flash the turnsignal indicators when the turnsignal stalk is not active or 4-way switch pushed in.

[bzettner]

Update, I dug and found the other end of the white w green wire, connected and the flashing brake light stops (works like its supposed to)

The brake light you talked about is the indicator in the multiple gauge correct? Was this wire broken or cut on purpose?

The original "flashing condition", while driving, included both dash turn indicators flashing WITH the brake light flashing. When I got home I "played" with the E-brake switch and added some brake fluid, though it was not really low. The brake light quit flashing at that point but the dash turn indicators continued, even after the faulty bulb was replaced. The next drive, it took about an hour before the brake light started flashing again.

The WH/GR wire appears to be broken or cut. I can't imagine how the wire could be cut/broken. I found the other end of it in the wire bundle behind the gauges, temporarily joined the ends and the flashing brake light stopped.

Yes, the flashing brake light is in the multigauge/brake light/gas gauge. altenator light/oil pressure light

[bzettner]

[/quote]The flasher should only operate when there's a load on terminal 49a. In the diagram, the only paths to ground are the 4-way switch, turnsignal switch or brake warning indicator.

One test is to remove the wires on the master cylinder warning switch under the car and the ebrake wires. Something is creating a load or leakage on terminal 49a.

If the new flasher didn't solve the issue then the original flasher should be ok and should be reinstalled. While the flasher is out, measure the resistance from the plug terminal 49a to ground. It should be infinite since every path to ground goes through a switch thus should be an open circuit.
[/quote]

As it sits, I have everything accessible, albeit a contortionist warmup exercise to use two hands and both eyes. I'll check continuity later today. Thank you for your help!

[bzettner]

When you say the turn signal indicators flash continuously is this with the key on and no turn signals on? Both flash?

Yes, start the car, shut the door, release the E-brake (stops the red flashing brake light) and the dash turn signal indicator lights both blink at the same time, continuously. If you put on the right or left blinker, they work like they should until the blinker is turned off.

Besides this, all lights, flashers, turn signals brake light, tail lights, hi/lo headlights and aftermarket fog lights all work as they have since 2013 when I got this car.

It is strange that the turnsignal indicators flash since there's a 2nd relay in the flasher to detect heavy exterior bulb current to power the indicators on pin K on the flasher.

The flasher should only operate when there's a load on terminal 49a. In the diagram, the only paths to ground are the 4-way switch, turnsignal switch or brake warning indicator.

One test is to remove the wires on the master cylinder warning switch under the car and the ebrake wires. Something is creating a load or leakage on terminal 49a.

If the new flasher didn't solve the issue then the original flasher should be ok and should be reinstalled. While the flasher is out, measure the resistance from the plug terminal 49a to ground. It should be infinite since every path to ground goes through a switch thus should be an open circuit.

I disconnected the master cyl switch wires and the e-brake wire. This indeed eliminates the dash indicators blinking, The e-brake female wire connector was falling apart. I replaced the female spade connector and feel all is well there. There is quite a bit of resistance from 49a to ground.

My next "look into" will be tracing the wires from the master cyl switch towards the dash to see if there is an apparent "bad spot"....hoping for something obvious (IMG:style_emoticons/default/wacko.gif)

[Spoke]

I disconnected the master cyl switch wires and the e-brake wire. This indeed eliminates the dash indicators blinking, The e-brake female wire connector was falling apart. I replaced the female spade connector and feel all is well there. There is quite a bit of resistance from 49a to ground.

My next "look into" will be tracing the wires from the master cyl switch towards the dash to see if there is an apparent "bad spot"....hoping for something obvious (IMG:style_emoticons/default/wacko.gif)

@bzettner

So the flasher circuit is working correctly now with the master cylinder switch wire disconnected from the switch?

Having quite a bit of resistance from 49a to ground is good.

[bzettner]

I disconnected the master cyl switch wires and the e-brake wire. This indeed eliminates the dash indicators blinking, The e-brake female wire connector was falling apart. I replaced the female spade connector and feel all is well there. There is quite a bit of resistance from 49a to ground.

My next "look into" will be tracing the wires from the master cyl switch towards the dash to see if there is an apparent "bad spot"....hoping for something obvious (IMG:style_emoticons/default/wacko.gif)

@bzettner

So the flasher circuit is working correctly now with the master cylinder switch wire disconnected from the switch?

Having quite a bit of resistance from 49a to ground is good.

Yes, with the MC switch disconnected, everything works as designed EXCEPT any advantage of having the MC switch working, yes?

I'm confused, I understood that 49a to ground should be infinity/zero resistance. Now I'm reading a lot of resistance is good. I'm a ignorant/learning electrical 914 guy, which is it? And, am I right to think there is a short to ground somewhere from the MC switch wires to the flasher plug?

Your help is very much appreciated, @Spoke ! (IMG:style_emoticons/default/beerchug.gif)

[Spoke]

I disconnected the master cyl switch wires and the e-brake wire. This indeed eliminates the dash indicators blinking, The e-brake female wire connector was falling apart. I replaced the female spade connector and feel all is well there. There is quite a bit of resistance from 49a to ground.

My next "look into" will be tracing the wires from the master cyl switch towards the dash to see if there is an apparent "bad spot"....hoping for something obvious (IMG:style_emoticons/default/wacko.gif)

@bzettner

So the flasher circuit is working correctly now with the master cylinder switch wire disconnected from the switch?

Having quite a bit of resistance from 49a to ground is good.

Yes, with the MC switch disconnected, everything works as designed EXCEPT any advantage of having the MC switch working, yes?

I'm confused, I understood that 49a to ground should be infinity/zero resistance. Now I'm reading a lot of resistance is good. I'm a ignorant/learning electrical 914 guy, which is it? And, am I right to think there is a short to ground somewhere from the MC switch wires to the flasher plug?

Your help is very much appreciated, @Spoke ! (IMG:style_emoticons/default/beerchug.gif)

If you take a switch and measure the resistance between it's terminals, with the switch closed (on) you should read zero ohms or a short. Very low resistance is a heavy electrical load. With the switch open, the resistance should be infinity; very high resistance; an open circuit; no current can flow.

It seems your master cylinder switch has either been tripped or is bad. Measure the resistance of the switch with all wires off of it. It should be infinite ohms. The issue sounds like it's the switch or something wrong with your braking system if the switch is functional and is ok.

What I don't understand is why the turnsignal indicators were also flashing. Only the brake warning light should flash if the MC switch is closed.

[bzettner]

@spoke

With the wires disconnected from the MC switch, measuring ohms from one prong to the other barely makes the needle on my meter move (high resistance). My switch is of the "not resettable" variety, 2-wire. So either the switch is faulty or perhaps it has done its job and something has changed on my braking system? My brake feel and stopping power is equal to what it has always been.

Ignorant master cylinder question, can the switch be changed out without brake fluid loss? Will this be a brake bleeding session after the switch change?

[Spoke]

@spoke

With the wires disconnected from the MC switch, measuring ohms from one prong to the other barely makes the needle on my meter move (high resistance). My switch is of the "not resettable" variety, 2-wire. So either the switch is faulty or perhaps it has done its job and something has changed on my braking system? My brake feel and stopping power is equal to what it has always been.

Ignorant master cylinder question, can the switch be changed out without brake fluid loss? Will this be a brake bleeding session after the switch change?

Sounds like the switch is high resistance. It should be infinity. The needle should not move if the switch is open. What resistance do you measure? If you have an older volt-ohm-meter it's a bit more difficult to determine an accurate measurement.

If you have difficulty determining the actual resistance just take a picture of the VOM during the test. I don't mean to insinuate you don't know how to read the meter but they can be tricky. I worked with a guy once who claimed an LED that I made didn't work because there was 12V on the meter. I said the wires might be reversed and the voltage backwards. He finally showed a picture of the VOM and indeed the measurement was -12V instead of +12V.

Also while you're there, try measuring each of the 2 switch terminals separately to chassis ground to see if either terminal has a leakage path to chassis ground.

About replacing the switch, it is likely that if the switch is removed fluid will escape and the system would need a full bleed. I'm not familiar with replacing just the switch. Maybe someone could chime in with some experience with switch replacement.

[bzettner]

@spoke

It’s been a long day and I’m out of town now, but here’s the resistance I measured this AM from one “spade” to the other. I also measured from each spade to ground and if memory serves me there was 0 continuity (needle movement) from each spade to the MC or frame near the MC.

I ordered a new switch from 914Rubber last night, one spade and resettable.

[Spoke]

Thanks for the picture. Looks like you're on the 2Meg ohm setting reading 0.889 which is 889k ohm. That's fairly high but definitely not infinite. Wouldn't hurt to change the switch.

[bzettner]

Thanks, @spoke . I’ll let you know what the outcome is!

[bzettner]

(IMG:style_emoticons/default/piratenanner.gif) My new 914Rubber, single spade, resettable master cylinder switch has been installed and has eliminated the odd dash turn indicator continuous flashing AND everything else still works as designed!

Thank you, @spoke ! (IMG:style_emoticons/default/beerchug.gif)