Technical Brake Light problem

I am wiring a 1930 Coupe with a Signal Stat 900 turn signal switch and Speedway 12 circuit wiring harness. For some reason whenever the ignition is on (running or not) my rear brake lights come on. When the ignition is off my headlights, brake lights, running lights, turn signals and hazard lights all operate as they normally should. When the ignition is on (engine running or not) all lights work as they should with the exception that the brake lights are constantly on. My ignition switch is a 1937 drop column On/Off toggle. The Signal Stat is wired like the following diagram:



Any ideas on where my problem lies? TIA, Tony

 

Have you checked the brake light switch? Sounds like it's bad or needs adjusted.

EDIT: I see the brake works fine with key off so I'd try another signal Stat, sounds like it's not releasing internally.

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Thanks lostone, the thing that throws me is that it works perfectly normal when the ignition is off so I was thinking the ignition switch might have something to do with it.

 

Is the car running? What I’m really asking is this happening with only battery power? If so is battery fully charged?

 

The car starts and runs, this problem occurs whether the car is running or not. The brakes light up whenever the ignition switch is toggled to the on position and stay that way.

 

Does the engine stay running if you hold your foot on the brake and switch off the key?

 

I dug through my files on the 900 switch and found the instructions for mounting it and I think that same diagram.

There should be no wire connected directly to keyed power on that switch. It all runs through the flasher. Normally the bigger trucks have the turn signals set to work ign on or not. That doesn't mean that you can't run the flasher off the keyed side though. Check the last page in that pfd I posted in the other post I did. it has some instructions for painless wiring kits that may apply to the speedway kit.

 

this is a link to a pfd flip page book with instructions for the 900 series switches Installation, Wiring and Operating Instructions for Pages 1-5 - Flip PDF Download | FlipHTML5

 

Sounds like there is a short between the switched power (ignition on) and the brake light circuit. As soon as the ignition switch is turned on, you have a constant feed to the brake lights. Check all wiring routes and connections.

Is everything supposed to work with ignition off or on? The wiring diagram doesn't mention getting power from the ignition switch. It shows fused power directly from the battery.

 

It sounds like you wiring is configured for both stop/turn brake lights and stop only which you cannot have. You have a battery feed to the turnsignal switch AND an ignition feed to the brake light direct from the fuse box. You need to disconnect this.

 

Not sure, I'll check that out tomorrow.

 

Thanks, Mr48chev, twenty8 and '29 Gizmo. I already have the Signal Stat wiring diagram and have wired it exactly as the drawing in my initial post shows which is from Signal Stat.

Twenty8, everything works with either the ignition switch on or off. When off, all lights work as they should. The TS gets power from the battery. I agree that power is getting to the brake lights when the ignition switch is turned on. It's tracking down that power source that has me stumped.

'29 Gizmo the TS switch is wired for both stop/turn and brake lights through dual filament bulbs like the diagram shows. If I were to disconnect either at the fuse box wouldn't I lose that portion of my light system?

 

I think the key is how the stop light switch is wired in. The ts switch takes over distribution of the power to the stop lights. There should be no other other connection to the stop light switch or stop lights than the ts switch or power to the stop light switch itself, the souce of which is not shown on the diagram

 

Additional information, I'm running this type two wire column drop. One wire is ground and the other is power. The power is supplied from the fuse box by the FAN wire; I'm not running an electric fan.

 

Gizmo, the Grey/Black wire in the diagram goes from the Signal Stat to one post on the Brake Switch. A wire from the other post goes to the brake lights. The brake switch is a hydraulic type.

 

Some thing does not seem right, the brake switch is an input not an output. If you are wiring the turnsignals to work through the brake lights, the brake light switch cannot connect direct to the brake lights., otherwise the brake light cannot be interrupted by the flashing function.


https://www.jalopyjournal.com/forum/threads/signal-stat-7-wire.1226273/

 

I think the first thing I would do would be to turn the key on and unplug the brake light switch. If the brake lights go out, you need to figure out why there is power on the switched side of the brake light switch with the key on.

If the brake lights don't go out, plug the brake light switch back in and unplug the flasher. If the brake lights go out, you probably have the flasher wired wrong or the flasher is faulty.

If one of those two tests doesn't work, then I don't know what your problem is. It will take some meter testing to see why/how the brake lamps are receiving voltage.

 

Thanks Gizmo, I see what your saying. I shouldn't wire the brake switch second pin to the rear lights. Would doing something like this video shows with a relay solve my problem? (2:20 into the video)? If so, is there a better way to do it? Thanks, Tony

 

Thanks jaracer, with the brake switch unplugged and the ignition on I still get constant brake lights on. I'm starting to think I wired the brake switch incorrectly by running one of the switch posts to the rear lights instead of where it should go.

 

No relay needed. The brake switch needs constant power to it, not switched. Other terminal from brake switch goes to turn signal per instruction sheet. Turn signal operation gets keyed power only.

 

Johnny Gee thanks, so one wire to switch from Signal Stat to one post on hydraulic brake switch and wire from other post on switch to battery power?

 

Let me reword. You need constant (fused) from battery to the brake switch (either terminal) (Note, the terminal that has nothing on it per your instruction sheet you posted is where it goes). Other terminal (one shown) when brake is applied sends power into the turn signal switch per your instruction sheet to be distributed to left and right rear brake lights at the same time.

Meaning the turn signal switch is what distributes the brake signal "from" the brake switch (both L & R) when in neutral position.

 

Sorry guys, brain fart on my part. I wired the brake switch correctly after all. One wire from Signal Stat switch to BS other wire from BS to wiring harness wire marked "brake switch". Still have the brake lights on when ignition is on problem.

 

Johnny I understand, my Brake switch has one wire coming from the fuse box labeled "brake switch" and the other wire goes from the Brake switch to the Signal Stat 900. I think all the wiring for the Signal Stat is as it should be. I've checked all grounds, even run temporary ones in addition to rule out a grounding problem with either the lights or the Signal Stat. I can't help but think that something about the drop column ignition switch wiring is the culprit.

 

Suggests a switched ignition wire touching someplace after the brake switch but before the signal stat.

Is it all tape loomed up? Any connections that sit together in a cluster that mighr have pulled slightly apart and are now touching?

 

PhilA, will check again. Wires loomed up and taped but will open up to confirm no interference.

 

The only power to the turn signal switch should be the keyed power to the flasher (s) and the power to the brake light switch. There is no other power going to that switch.
It's not in the ignition switch it is in the wiring between the ignition switch and the flasher. If it was beyond the flasher both brake lights would flash just like 4 ways. Go back along that brake light wire and track it all the way from the brake light switch to the turn signal switch. Every inch.

 

Dual filament bulbs (1157) need 3 wires
Low (running) high (stop/turn) and a ground.
the low side comes off the light switch
The high side comes from the turn signal switch. The TS switch provides the logic as to which bulbs light when.

That diagram doesn’t show the 3rd wire, but clearly the bulb is dual filament if the fronts are drawn as single.

 

Thanks 31Vicky, I am using 1157 bulbs and they are wired with the 3 wires you mentioned. As I posted all lights work perfectly normal with the ignition switch off. When the ignition switched is flipped to the "ON" position the brake lights go on and stay on. All other light functions; turn signals, head lights, running lights and hazards work normally. Still trying to find out where power to brake lights is coming from when ignition switch is on.

 

It’s there (rear only) but not the best diagram lay out for the general public.

At this point I’m going with faulty blinker switch unless op starts showing some multimeter test results.