Brake fluid/Handbrake light stays on

I have a 69 s2 that I bought late last year. I have been working on it constantly trying to work out all the minor problems with the car. I started a road trip yesterday only to find my Brake fluid/Handbrake light was on. It was not on when I parked it in the garage Friday night. Checked the fluid levels and the front bottle was low so I added some brake fluid to top it off. The light was still on. Since I was sure it was not for lack of fluid, I continued on my 150 mile trip for my granddaughter’s birthday. No problems on the 300 mile round trip with the light still on. This morning I checked everything and the light was still on. Suspecting the sending units on the lids, I checked them with my ohm meter. All four wires showed continuity to ground. Checking the terminals on the caps, both showed continuity with it’s partner. When I pulled the pin up, I lost continuity. Does that tell me that the floats are doing their job? Or should it be the other way around? Should the light come on with continuity or off with coninuity? Also, with all the wires disconnected, I still had the light on. Some of you may say that it might be the handbrake switch, but that hasn’t worked in the 10 months I have owned the car. So I ruled that out. What am I missing? I just hope it’s not something simple that I have overlooked! If so please forgive me.

You describe the light still being on with the reservoirs full, then going off if you pull the pin up.

It seems that your handbrake switch doesn’t affect the light at all.

So the problem is likely with the sender units. The floats may be full of fluid.

When the spring breaks on the handbrake switch it leaves the light on. These springs are known to break…

My guess is it’s the handbrake…… out with the console…… or you could just leave it…… mine decides when the handbrake is on …… based on the roughness of the road :joy::joy:

No, the light stays on no matter what! I mentioned that when I pull the pin up, I loose continuity between the two terminals on the cap. I also ran jumper wires between each of the cap wires to complete the ground circuit, light was still on. I knew some would mention the handbrake switch, and I am not ruling that out completely, but as I said, the handbrake light NEVER came on. That would lead me to believe that it was already defective. Why would it all of a sudden cause the light to come on? Also, the light is steady. Never flickered once that I am aware of on the 300 mi. trip.

Edit: Is there a way to disconnect the handbrake switch? There must be!

Look at your schematic. They’ll be a bullet connector in the right a pillar area.

I think you have two problems…

If you have to ‘pull the pin up’ even when the reservoirs are full then your floats aren’t (floating). The usual fix is to remove the unit, pull off the metal tube and replace the corks. I used wine corks, some prefer plastic ‘corks’.

Meanwhile - sounds like your handbrake switch may also be failing to work. It is a very finicky adjustment. Right now I have one that leaves the light on until the tunnel warms up and then it goes off - just a small bit of heat expansion is the difference.

To get at the switch requires removal of the seats, radio console and center console.

BTW - worth noting that the dash lamp always has white wire power (ignition on) and the switches in the bottles and on the handbrake illuminate it by providing a ground.

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Thanks again Geo! i just happened to save two corks for just that purpose. As I stated above, I have continuity at the terminals of both bottles, which means the ground circuit is completed. If I interpret this correctly, this would complete the ground circuit which would then turn the light on. Is this correct? If I pull the pin up, the circuit is broken and this would keep the light off?

You might also make sure the metal wafer on the float rod and and contact tabs inside do not have any corrosion. I had to clean mine up some when the light was not working well.

68 E-type FHC

Correct - provided none of the other sources (ie the other brake reservoir bottle or the handbrake switch) were completing the circuit, as all 3 switches are wired in parallel.

Understood. Any of the three circuits closed on the ground side would energize the light. Removed both brake bottle caps as they both seem defective. You can see the cap on the right needs to be replaced, however it should still work with a new cork until I get a new one. The tubes are staked onto the caps. Do I just pull them off and then just press them back on? I read somewhere on this forum that you can use a dremel to cut slots in the top rivets and then use a screw driver to unscrew them, Does that make sense or did I misunderstand that?

In my experience, the tubes just pull off. The “rivets” used to hold the tops together are actually threaded, with a very coarse thread. I’ve found that they will back out by gently prying between the upper and lower halves. I never found it necessary to cut a slot in the head.

I have both brake reservoirs working as they should. Brake light is still on! I disconnected the wire to the light since it is doing me no good as it is. So, it must be the handbrake switch. I would at least like to have the brake reservoirs working as they should since I consider this WAY more important than the handbrake. I am not going to tear the car apart to fix the handbrake light. Does anyone know how I can disconnect the wiring on the handbrake so I can reconnect the light. That way I will at least have the warning light for the brake fluid level.

I have the same problem, the same need and the same reluctance to remove the radio housing, the console and the driver’s seat just to adjust that switch.

The wire to the switch runs along the passenger side sill, then across behind the seat to the tunnel. Break that circuit anywhere and you can have the reservoir sensors work but disable the handbrake switch. The circuit is never hot - it merely provides a ground that is interupted when the handbrake is fully released.

I do not recall a bullet connection anywhere on that run, maybe there is one under the dash. The wire is red/green.

If I cannot find a bullet connection under the dash then I may remove the passenger seat (pretty easy) and peel back the interior trim enough to get at the wire along the sill or rear bulkhead to cut it, install bullets and leave it disconnected for now.

Okay - I looked but could not find a connector under the dash on either side though with AC there is much I cannot see on the passenger side.

While looking I found that my light is now working fine (off when handbrake released) possibly because it is a hot day. So I’m done for now.

I had hoped to find them here (remember they are red/green - lots of green/red in there):

The wires to the lamp are braided and have lost their outer layer so all I see is black - going to be hard to work backwards from there:


Not sue about series 2 but in series 1 the red green comes via the rh loom …… this means that there is a bullet connector where that loom attaches to the main loom…. Looking at a wiring diagram that would suggest the same is true of a series2

Thanks all. I will have my son to help me look for it tomorrow. We have a full house this weekend. Kids and grandkids here for the weekend.