My “Brake Warning” light is staying on with the ignition is on / engine running. Brake fluid level is fine. Brakes work fine. When I press the test button on the brake fluid reservoir the brake warning light stays on and gets brighter. When I unplug the two wires leading to the float sensor - the brake warning light stays on. Earlier threads discuss that the brake warning light is also connected to the seat belt buzzer. I do not hear the buzzer (a good thing!). https://www.ferrarichat.com/forum/threads/brake-warning-light-88-tr.421991/ My car is a 1986 single mirror car. I am not sure but think I read somewhere the circuit is different/ simplier in the early Testarossa. Any help would be appreciated as I just moved the car to a different state and am trying to get it inspected and registered. Inspectors don’t like warning lights stuck on!
The 348/85 OM for 1985/86 US version TR says that it should have one (see page 37), but it's only "active" for the Driver's seat belt. Very common for these various buzzers to be unplugged/disabled. Unfortunately, I don't have a schematic for 85/86 US TR so can't comment on it much, but the online 1985 TR SPC shows that it's the same little combination ECU/speaker as used on the later US TR -- item 13 here: https://www.ferrariparts.co.uk/Diagram/ferrari/testarossa-tr-85/122-valves-and-electromagnetic-switches?part=61268300 Does your brake warning light illuminate during starter motor cranking?
Yes, the Brake warning light stays lit during starter motor cranking. Brake Warning light comes on from turning on key, thru starter cranking and stays on once running. Misc Items I noted: The float switch on the brake fluid reservoir has two leads - one with a black wire and the other with two Pink/Black wires Seat belt warning light on the center stack stays lit all the time (even if seat belts are engaged)- not sure if this is a new thing or if it is related. Seat belt buzzer is not sounding. I also noticed that the door open buzzer is working properly when the door is opened. The small red dome light on the drivers door is not lighting when the door is opened. Not sure if any of this is related at all! Thanks for your help!
As I said, I don't have the schematic for an 85-86 US TR so can't do a deep dive, but none of this sounds good for that little specialized ECU, and my suggestion would be the same as in the other thread -- try unplugging that specialized ECU. If the brake warning light goes out = you probably need a new one. If the brake warning light stays "on" = probably a pinched wire somewhere shorted to ground. Almost certainly not related. The lights in the doors are controlled by the switches in the door jams which gets their ground from being mounted in the door jam plates -- so easy to have some corrosion or bad connection there. Or the door jam plate can have a bad connection to the chassis (like if someone painted the backside) -- so check those screws/mountings, too. Is the (white IIRC) light in the bottom of the door also not working? Also, do the Driver's door lights work when you open the Passenger door (I believe they should) -- if so, just more evidence that you have a bad ground at the switch on the Driver's side or at the Driver's side door jam plate.
Thanks Steve. I will unplug the small ECU / speaker (item 13). Hopefully it makes the light go out so I can go get the car inspected and registered while waiting for the part to arrive. The ECU looks to be hidden behind the fuse panel, hopefully it isn’t to difficult to access it. Brian
I unplugged the ECU buzzer (item 13) and the Brake Warning Light has gone out. Problem solved! It was a bad ECU. Thanks Steve for the suggestion. The car passed the AZ emissions/ safety inspection also! I’ve posted some photos to possibly help someone in the future. The ECU is accessed by removing the fuse/ relay panel in the front trunk which involves removing 2 Philips screws on the top of the panel. My 1986 row of ECUs did not have the same number of modules as shown on the drawings. Also, I was looking for a ECU with speaker / buzzer holes in it but none of them looked like that. The module to the right said “Acoustica” on the side. The unit was mounted with the speaker holes pointing towards the rear of the vehicle. Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login
Side note: Removing the seat belt ECU seems to have silenced the drivers door open buzzing and put out the seat belt warning light on the center stack.
