Hi peeps

Hit the drags locally (Perth, AUS) last Wednesday and as i was going down the pass the E-Brake light came on - looks like this (!).
I was in fourth gear at the time doing about 140kph (90ish MPH)
I checked the handbrake by pushing on it.
After the pass i parked up and turned off the car turned the key back on, light was still there
I pushed the handbrake down - light stayed on
I checked if the roof engaged with the handbrake down - it didnt and light stayed on
so its not the handbrake

I then unplugged the the Mastercylinder float switch - light stayed on
Fluid was not low either and float seemed to be floating as usual.



From the diagram i gather thats all there is to it, with all ends open the light should not ground.
If its shorting where would it be is it common?

I think it cant be shorting on the handbrake side of the circuit otherwise the soft top would be functional even with handbrake down.
only other thing i can think of is a short on the float switch side.

Anyone got any ideas to diagnose?

 

I understand you disconnected BOTH the connection at the parking brake and master cylinder? And the light stays On? Or is the parking brake still connected? Time to pull both.

The next page in the shop manual shows how to test both switches.

-- Chuck

 

thats right it shows how to test for both if the light is failing to come on though

I didnt pull the Handbrake cable out because with the handbrake down the soft top is still not activating. the soft top can only activate if the hand brake is up to provide earth for the light and the Convertible Control module, or if its shorted somewhere on that side of the circuit.

i have also tried disconnecting the Convertible module as well in-case that was playing with it.

and i was checkign the light with park brake down, Float d/c'ed, and soft top was not functioning (because park break disengaged) with all of this the light was still on.

 

My only suspect is the Grn/Red wire from the brake master cylinder is grounded somewhere between there and the instrument panel. If the other wire was grounded the roof, etc would work all time as you note.

 

I think ill disconnect the float again and poke a multi meter down both sides of the plug of the loom.
that should tell me if we have a short right?

 

There's just those two wires in the connector. Set your Ohmmeter at its highest resistance. Connect one probe to the car body. Black wire should show no resistance (zero Ohms) -- or beep if your meter does this-- between it and the car chassis since it should be connected there already. The green/red should show infinite resistance to the car body or the black wire connection or no beep.

Powered test light works just as well, I have a box of ohmmeters and not a single powered test light.

-- Chuck

 

If you haven't had this car since brand new, check to see if the previous owner messed with the 'softtop down at speed' mod. They can sometimes screw with the handbrake wire to fool the softtop module.

 

I did check that, and since the light has been on i did that mod for fun by depinning the VSS wire from the plug.
However the Hand Brake wire was still intact and if it had been shorting out there the soft top would have been operating with the hand brake off anyway, but thanks for the note.
I havent had the car since new, only 2 years

I will be checking the float switch connector in the coming days

 

Time to finger the float.

Remove the top to the master cylinder. Remove the filter screen. Finger the float to break it loose. Replace filter screen. Check fluid level. Replace cover.

Thank Utah . Sometimes the mold flash on the float sticks to the float guide (rib). Most likely you sloshed the fluid during launch and it stuck.

 

Thanks for the suggestion, however i tested that by unplugging the float and the light stayed on