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Hood microswitches

Started by AcemanToo, January 24, 2022, 16:37:07

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AcemanToo

Does anyone know where all of the hood microswitches are located please? I know there's one on the handbrake and another one on the driver's side hoodframe but I'm guessing that there are more hiding away somewhere! Any help most welcome and appreciated!

Wally

Almost sure there are switches on the end of some of the hydraulic rams also the body panel that opens to raise the hood has one on the catch.

paho

As Wally says I think each hydraulic ram contains "sensors" which indicate the position of the piston. I don't have pictures and can't recollect where exactly they a positioned on the rams. As you say there is a micro switch on the hood frame (blue+black wires) which I guess indicates the hood is in the locked/unlocked position, its just under the flap that hangs over the side window where the hood bends when you lift it, on the right hand side. I hav'nt managed to find the hood cover and brake micro-switches yet. Planning of new kitchen is getting in the way!
/Paho
"Blessed are those that don't ask for they shall not receive"

AcemanToo

Many thanks Wally and Paho! The search begins!

Wally

As far as i know, all the sensors are just plain on/off switches.
Just think about how the system needs to work.
The hood should not operate unless the handbrake is on, hence a switch.
The hood cover should not lift until the catch is released so that will have a switch.
The hood cover will need to be fully open before the hood lifts out, so there will be a switch on the cover ram.
Once the hood is out a ram switch will be operated to allow the cover to close.
Once the cover catch switch is closed it will stop the cover rams being operated and then expand the hood fully until the switch on the o/s operates (hidden in the hood material on the mechanism).
At this point the process is finished as you pull the roof front down to lock.
Opening is just a reversal of the operations.
I would say it is rare for the control unit to fail, nearly always lives, earths or switches.

Good luck

AcemanToo

Many thanks for such a detailed reply! All quite logical when you see it set out like that!

paho

Despite storm Malik, took a trip to the garage today to take some photographs of the sensors mounted in/on the roof hydraulic pistons. You can access them by removing the cover held by one screw. See pics attached with cover on and removed. The next two pictures show the sensors mounted on the pistons (red arrow) and the connectors (green arrow), the sensor on the inner piston is not easy to see in the posted pictures.
I think the sensors are Hall effect sensors. There should be three wires from each sensor, black earth lead, yellow and red leads indicating if the piston is extended or not. What colour the wires are on the other side of the connectors I have no idea. These sensor indicate which position the top stack and bow parts of the hood are, open/closed  and up/down respectively. I think it is highly unlikely the sensors are faulty, maybe a connection fault or bad earth.
If you have already found the handbrake and hood microswitches there are two more hiding away somewhere associated with the cover being open or closed; I hav'nt found these two yet.
/Paho
P.S. Have you pushed the manual release catch to its locked position? (page 2.22 in the manual). I have a vague recollection that the gear lever should be in neutral too.
I did a state table two years ago to document the sequence, there are about 15 to 17 "states" for the hood to go through depending on whether it is being lowered or raised.

"Blessed are those that don't ask for they shall not receive"

AcemanToo

Gosh! Thank you for the photos and the explanation! I'm going to try going back to basics by starting at the ignition switch and then working on from there. The power hood warning light doesn't do anything at present so I suppose simple voltage checks along the route to the rear of the car would be a good start. I'll post my findings as the search progresses!

manxlowflyer

Included in the hood operating instructions there is reference to the electric side windows which states that they will automatically lower when the hood is operated, possibly more switches there then!

A small addition, I have been having trouble both raising and lowering the hood which seems to be worse in hot weather, also the emergency release Bowden cable was broken so I set about removing the panels in the boot and at the front of the fuel tank.
On removing the broken Bowden cable I noticed that the hydraulic reservoir seemed to be full to the brim, the hood was in the lowered position, I removed the filling plug and a gush of hydraulic fluid escaped from the filling hole. As there has never been any leaks from the rams etc in my ownership I have never added any fluid so I assume that the tank was filled with the hood closed which has prevented smooth operation as there was not enough space for returning oil during the cycle to go into the tank when opening and therefore stopping the hood operation.
After the removal of a little more oil and an air gap at the top of the tank the hood is now operating.

I hope this finding is of some use to other owners.

paho

I think the window lowering is done by a relay in each door, passenger side on mine doesn't work.
When dismantling my hydraulic pump I noticed the oil level marked on the side of the resevoir. This can't be seen easily when the pump is fitted.
I made a dipstick using coat hanger wire to check the level. I'll post a picture with dimensions .... if and when I can find it....

I'm curious how did you remove the panel at the front of the fuel tank?

/Paho
"Blessed are those that don't ask for they shall not receive"

Max Allan

The cover catch mechanism is accessed via the cockpit rear trim panel. The cover is removed by first removing the L/H & R/H quarter trim panels (held in by one screw per side accessed with the hood cover open. Once screws are removed slide panels forward to release them where they clip to body door shuts. The rear vertical panel is held in by two screws concealed under the rear edge of the carpet. Once removed, lift panel vertically to release it from two retaining clips located towards the upper part of the panel (easier with hood cover open).   
The catch mechanism also incorporates the micro switch which signals ecu the cover is released and can begin hood operation.
On my car the hydraulic ram micro switches are located internally in the offside (R/H) ram bodies.

Hope that helps. Max

manxlowflyer

Mine is a little different, the quarter trim panels are the same but the rear trim panel is slotted onto brackets at the top and bottom attached to a metal plate shielding the fuel tank. Once the trim is removed, at the top of the metal plate there are 4 slotted screws and one bolt (which has a thick spacer behind) to be removed and 2 screws with upholstery washers which go through the carpet at the bottom. When this plate is removed the fuel tank is exposed as well as the solenoid release for cover unlocking. Whilst the tank was exposed I found that the flange bolts for tank sender etc. required nipping up too, hopefully this will cure the slight whiff of fuel I have been smelling.

paho

I promised to post a picture of the dip stick I made for the hydraulic oil tank on the roof pump, but covid and the installation of a new kitchen got in the way.
Unfortunately the marks I made don't show up very clearly, so I have measured it and its 3cm to the "full mark" on the tank. I tried to double check this yesterday
and it seems correct but without removing the pump I can't be 100% sure as the level marks are hidden! (The reason why I made the dipstick!).

/Paho
"Blessed are those that don't ask for they shall not receive"