Okay, I know this project won’t necessarily interest everyone, and many would consider it severely over-complicating an adequate system – but for those of us who like to see what can be done to make life that little bit easier, here goes….
Well, having tried a few weeks ago to get the hood cover (tonneau cover) to release with an electrical system which ended in abject failure due to the required pull on the cable being far in excess of the solenoid I had purchased (burned it out on the first attempt), I re-visited it today with a different mind-set.
The OE cable works well enough, but does require a good pull (on my car anyway!) to release the 2 catches. This is due in main to the release system whereby 1 cable operates 2 catches via a pair of levers inside the catch holder brackets.
I frequently needed to push down on the cover to take pressure off the catches whilst pulling the cable – not always an easy task to reach everything whilst applying enough force to the cable to work the mechanism.
The actual catches are exactly the same as the boot catch - but using 2 of them – and as the boot opens easily with a solenoid, it couldn’t be that hard to make it all work….
Once you take the plastic cover off (2 small self-tapping screws) it is apparent that the metal rods from the leverage mechanism work in an inefficient plane (90 degrees from the cable movement), and therefore an awful lot of force is required to get the required movement at the catch.
The actual mechanism doesn’t need much force at all to operate; it just needs to be applied in the right direction.
It took a bit of thought (about leverage principles), but wasn’t at all difficult to achieve.
I needed to purchase 2 bicycle cables (I went for stainless steel Teflon coated gear cables, as they are thinner than brake cables which makes the crimping a bit easier, but brake cable would also work), I still had an unused solenoid from my earlier purchase of 2, some suitable bolts and some 10mm aluminium plate left over from my seat brackets so nothing else to be bought. As Halfords currently have Universal gear cables for £1.99 each it wasn’t a hugely expensive project.
Firstly, I had to route the cables – easy on the drivers (right) side, but a little harder on the left as the petrol tank is right below the bracket. I drilled a 10mm hole at the bottom right-side of the steel bracket and job done.
I made up some cable-end brackets from the aluminium plate – each one was made from a bit 10mm x 15mm x 40mm (approx.), and as they can’t be seen the exact size/finish is fairly irrelevant, as long as it does the job. A simple case of drilling a 2mm hole through the width (15mm) of the metal, then opening the hole out to 6mm for 10mm depth. Then a couple of 5mm holes across the other face for the fixing bolts.
2 are the same, and the 3rd is similar, but with 2 holes next to each other, approx. 10mm apart (2 cables).
Fix the 2 aluminium cable ends to the inside of the current brackets, angled slightly away from vertical, so the cables run in a straight line between where they enter the bracket and where the release catch fits (obviously, they fit with the 6mm hole downwards!).
Push the inner cable through the sleeve and fit the end of the sleeve into your aluminium block (probably easiest to do these bits before actually finally bolting the blocks to the bracket!). Then loop the cable through the end hole in the lever at the back of the catch (again, easiest to remove them first, and take the metal rod out of hole!!) Crimp the wire loop (I used standard blue wiring crimps, but removed the insulation to leave the metal bit) – again, it is obvious that you need to have fed the crimp over the cable before forming the loop, but I’ll state the obvious anyway.
Feed the cable so that it is all running freely and snug in the blocks, then refit the catches and tighten up the bolts holding the blocks to the brackets.
I fitted the solenoid to a piece of steel plate which I had lying around, and cut it to the right size to fit where I wanted to mount it, but you can fit it wherever you want. It needs to be on a plate to give suitable rigidity to the system, as the other aluminium block mounts to the same plate, and without it, you would have to engineer some way for the solenoid to actually operate the cable, not just pull the whole lot!
The 2 cable inners loop through the solenoid bar and crimp to each other (that makes more sense if you see the picture). You need to adjust the amount of inner cable so that the catches operate within the movement of the solenoid, then do up the crimps, trim the cable length and move on.
Arguably, the plate with the solenoid could just be left lying anywhere, but you need to make the cable runs as smooth as possible, so I mounted it to the roll hoop side mounting – it is easy enough to fit in the same location if you haven’t got LGM hoops fitted
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Wiring was simple as I already had a solenoid in that area for the fuel filler cap release so there was a fused supply right next to it, but assuming that you haven’t got that, it’s easy to run a fused (4 Amp) supply direct from the battery (which is only a foot away) to the green wire on the solenoid. The blue wire I extended and ran through the bulkhead (between the hood frame mounting and the B post cover, no drilling or cutting required to that part) and used the push button which I had previously utilised for the boot release (which has since been adapted to release from the key fob, so the switch was somewhat redundant). It is a standard Saab boot release switch (any push-to-connect switch will do) mounted on the B post trim, just above and inboard of the old pull cable location.
- It’s an old pic of my old car, but I can’t be bothered to take another pic which would show the same switch in the same location
The other side of the switch just goes to earth.
That’s all there was to it, and the solenoid is plenty strong enough to pull 2 cables and release the 2 catches when it is aligned properly – the only really fiddly part was getting the inner cable lengths correct, and that only took about 3 minutes. I suppose that if you engineered the system slightly differently you could incorporate a couple of cable adjuster sleeves, but I didn’t think it was necessary. I might change my mind as and when the cables settle and/or stretch and I need to re-crimp the wires a bit tighter, whereas a simple twist of an adjuster would make it an easy process.
There is a potential problem with the whole system – if the battery is flat (or the fuse blows), or the solenoid burns out, then you can’t open the cover – and sods law states that it will happen just as it starts to rain and you want the lid on, but all is not lost.
I’m sure that you could either leave the original bars in place so that the OE cable pull remains (but I didn’t), or you can easily reach over the rear bulkhead to the catches (even with roll hoops fitted). As such, I drilled a 10mm hole in the middle of the plastic cover and fitted a rubber grommet. In event of a failure, simply remove the grommet and you can see the wires/catches and a quick tug of the wire, or poke of the lever with a small screwdriver will easily release the catches.
Having also (a while ago) replaced the fuel filler release with a cable/solenoid system, I have been able to remove the 2 cables from the door frames, and the remaining holes can be either filled & painted, fitted with a rubber grommet, or an M8 bolt with a nut on the back.
It all looks a lot tidier, and I can open the cover easily – even if I need to press lightly down to take the pressure off the catches it is so much easier to press a convenient button than pull a cable the wrong way!
It is obviously easier to do if you can remove the plastic liner tray, but it is possible with it still in situ (but you need to remove the right-side end cover to access the wheelarch space to stick the solenoid down there
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