Blinking Dash lights... help....

op3 · 12-18-2002, 04:48 AM

Hi All..
I'm in the final stages of putting my car back together, almost 3 years in the making. I've got most of the electrics figured out except those darned brake/seatbelt lights on the gas cluster, can't get them to stop blinking. I've placed an oil temp gauge in place of the red blank (c/o NorthHollywd Speedo). From reading the owner's manual, it sounds like when the engine starts running it is supposed to turn off. I've switched to carbs and its a
72 so no ECU or crazy interlock relay. I've clipped off the seatbelt wiringsocket and the pass. relay, which leaves me one yellow wire and two grounds. Grounding the one yellow wire only turns on the Fasten Seat Belt light on. If I'm reading the wiring diagram right its an open circuit normally so having the wires detached should have no effect, other than the FSB light not working. What gives? Does the ECU or something else normally tell these guys to turn off or what? Also to note, I've also replaced the brake MC with a newer 19mm one but retained the original switch from the old MC. Parking brake switch and door switches seem to work properly. Any ideas? This one has me stumped.. attached is a pic i took a couple weeks ago.. let me know what you think..
Thanks..

Chris

John Rogers · 12-18-2002, 05:20 AM

Unplug'm unless you need a light to tell you you don't have a seat belt on?

kellzey · 12-18-2002, 05:29 AM

John, he's talking about the parking brake warning light, not the rectangular seatbelt light.

Chris, there is a small white switch (under a rubber cover) on the master cylinder. When you replaced the MC and bleed the brakes, you need to reset (push in) that little switch. That should solve your problem.

This is a common issue. Search the archives for similar posts.

Good luck!

Karl

op3 · 12-18-2002, 05:39 AM

I've searched the archives and ran across that being a possible problem/solution but for the life of me i cannot find or see a reset button.... the only rubber boot is the one that goes over the switch where the two wires attach. I bought the MC semi-used from someone else so i don't know what year or model # it is (perhaps they are all the same anyhow). I've tried grounding them but still no dice.. any other possible solutions? where exactly is the reset switch supposed to be? there is one spot where there is just screw or bolt inserted, perhaps the switch was taken out and replaced with that. Unfortunately i think i tossed the old MC..... drats... does anyone have a pic of where on the MC it is supposed to be??
Thanks..

jackmech · 12-18-2002, 08:26 AM

First off, the flashing light is linked to the parking brake so make sure you have the parking brake released and also make sure that switch is in fine working order.

I was able to make my light stop flashing by swapping the two wires on the master cylinder (I don't have a reset button either). This is one of those things that shouldn't work, but did for me.

Can't stress enough to make sure the parking brake switch is working and the parking brake is released. If one of those isn't working, don't even climb under your car.

Dave at Pelican Parts · Dave at Pelican Parts's Garage

Two things make the light go on. (It blinks when it's on.)

If one of the wires (the one that isn't solid brown) that goes to the brake master cylinder switch gets shorted to ground, the light will blink. The function of the switch is to short that wire to ground when the piston inside the MC moves. There may be a reset button hidden inside of that rubber cover; press it. The second wire, on the switch with two wires, is a ground. The one-wire switches just ground through their threads.

If the wire going to the little button underneath the handbrake gets shorted to ground, the light will go on. The function of the button under the handle is to short that wire to ground when the button is NOT pressed.

Unplugged wires can easily short to ground, as can wires with broken insulation.

--DD

John Rogers · 12-18-2002, 12:55 PM

Hummmm, I feel the same about the brake warning light which will most certinly cause a storm of comments. Many new or replacement m/c's don't have the resetable switch and if the wire to the e-brake switch gets a short it is a huge pain to have to replace the wires as the run in the tunnel and under the carpet, etc. I guess I learned to drive before they were included in cars and never relied on them? Good luck.

philinjax · 12-18-2002, 01:08 PM

Another posibility is that either your front or rear brakes are not totally bled, so that every time you depress the brake, you activate the brake warning switch on the master cylinder.

Trouble shoot it: Pull the wires off the MC and disconnect the wire from the hand brake switch. If the big red light on the combo gauge still flashes, then you have a shorted BR/YW wire from either the hand brake switch or the MC. If this is the case, then separate the two BR/YW wires on the back of the combo gauge. Check each of those wires for continuity to ground. Then you will know which of the BR/YW wires carries the short.
My guess would be that the wire from the hand brake has somehow become shorted to ground at or near where the former seat belt warning relay used to be.
Phil

op3 · 12-18-2002, 02:19 PM

I'm pretty sure that the p.brake switch is good, there isn't much to it.. I've cleaned it and scraped off all the crud from years gone by so the contact should be good.. I know i tried switching the two wires on the MC awhile ago, but that did not seem to do anything.. maybe if i'm lucky, it will do the trick tonight.. I'm fairly certain the wires going to the p.brake switch are good. I noticed some chafing of it when i had the whole harness out and taped up those spots but perhaps i missed something.. Will try some of these things tonight and report back tomorrow.. thanks for all your help..
Chris

korijo · 02:29 PM

Hey y'all, he said he used the OLD switch, from the OLD MC. The new MC switch has the reset button, right? Mine does. And my old stock one didn't. Or am I $+0n& again............

BTW I have a pic, but the camera aint here. Soon.

korijo · 12-18-2002, 02:38 PM

Here you go. Little black button.

Dave at Pelican Parts · Dave at Pelican Parts's Garage

Some old switches have reset buttons, some don't. The ones that don't do not "latch"; they go open-circuit as soon as the piston inside the cylinder bore moves back to the "normal" position. The ones with the buttons will stay connected until you hit the button to turn them off.

I suggest checking the lug that the brown/yellow wire hooks to. See if it is grounded. Also check the lug on the handbrake switch. Disconnect both, then check to see if the wire is grounded. If so, then it is likely that the wire itself is the problem.

--DD

mike95125 · 12-18-2002, 10:22 PM

Hey Korijo! Is that POR-15 on that MC

fiend

korijo · 12-18-2002, 10:44 PM

No, I wish. Just you wait. I just got my new, little 10 gallon sand blaster, and a cheapie spray gun. I'm gonna P-15 the whole car.... Not really. Just the metal

op3 · 12-19-2002, 08:50 PM

Well.. I guess it goes a little deeper.. unfortunately work has gotten in the way, and haven't had time to dig into it much more than a hour or so last night.. did make a couple observations though...
-the p.brake switch wire isn't grounded. so its good..
-unplugging and/or reversing the wires to the MC had no effect.
-the wires are brown and white not br/yw, if that's worth anything
-both of the wires to the MC were grounded, one completely but the other just slightly.
-upstream from the MC cylinder the wires have a couple female connectors. I found that when i jump the two together the alternator light stops flashing.. is this right or is there supposed to be some relay or something there?
-the br/wh wire also seems to go over to the heater controls, i had them set up so that the light was working w/ the fan controls but i also think that is what was grounding the one MC wire.. So i guess i have a problem there too.
So with all that said it seems that the issue may not be with the switch at all. Definately cannot find a reset button though...
Man, I never thought that putting together a car from scratch would be this hard.. Maybe i should have picked an easier car to rebuild for the first time..!! Unfortunately i may not be able to mess with it again until after the holidays.. vacation is finally coming....
Any help is much appreciated...
Thanks..!
Chris