BrianY Posted June 3 Report Share Posted June 3 Hi everyone. I am in the process of restoring my Mk1 Vitesse and have fitted a new wiring loom. I have managed to get everything working ok with the exception of the overdrive. You have kindly given me sage advice on other topics and I would welcome your thoughts. I have always assumed that the O/D only operates when third or fourth gear is engaged and it is prevented from operating by an inhibitor switch on the gearbox which is open circuit when first and second are engaged but closes when third and fourth are selected then allowing control of the solenoid from the column switch. I have checked all my wiring and it seems ok so I looked at the inhibit switch which I found was showing open circuit on gears 2,3 and 4 but closed on first gear! Therefore I could only engage the overdrive when in first gear! When first is selected and I operate the column switch I can hear and feel the relay clicking so I think electrically its all ok but that the gearbox/switch mechanical interface is incorrect. Its a new switch which I just screwed in but I am now thinking that there might be a way to set it up!. Any advice please and thanks. Link to comment Share on other sites More sharing options...
johny Posted June 3 Report Share Posted June 3 Unless you have a non standard set up the switch is operated by an arm on the end of the 3 rail gear selector rod. Its operation is easily visible on the top front of the gearbox as the arm only contacts the switch button when the gear lever is lent over to the 3-4 position. Its shown in the free workshop manual👍 Link to comment Share on other sites More sharing options...
Pete Lewis Posted June 4 Report Share Posted June 4 it is a simple bell push switch there are two cam types on the remote fitted to an extended remote rod one is a cast and machined cam the earlier was a fabricated lever cam , they should only contact the switch plunger when as said the lever is held to the right side of the H gate ie yes just 3./4th to operate in 1st is making me think the cam/remote rod are incorrectly assembled early fabbricated cams did also operate a similar switch on a bracket the opposite side to the OD and this did the reverse lamps before they introduced the top cover reverse switch so what type of cam is fitted and what side of the remote is the bracket fitted ???? Pete Link to comment Share on other sites More sharing options...
Colin Lindsay Posted June 4 Report Share Posted June 4 It's a simple basic circuit - power comes in from the battery to the switch, along to the inhibitor, to the solenoid, and then to earth (My J-type has no solenoid on the bulkhead, but the concept is the same). It needs both switches, column / gearlever or inhibitor closed to work. Where did you get your inhibitor switch from? Is it possible that it's incorrect so that it makes contact when fully out, not depressed in, so your remote cam is actually turning it off not on? Incidentally, weren't there some of the TR range that had overdrive on 2nd, 3rd and 4th whereas 'our' cars only had the latter two? How did that work regarding an inhibitor? 1 Link to comment Share on other sites More sharing options...
GFL Posted June 4 Report Share Posted June 4 4 hours ago, Colin Lindsay said: It's a simple basic circuit - power comes in from the battery to the switch, along to the inhibitor, to the solenoid, and then to earth (My J-type has no solenoid on the bulkhead, but the concept is the same). It needs both switches, column / gearlever or inhibitor closed to work. Where did you get your inhibitor switch from? Is it possible that it's incorrect so that it makes contact when fully out, not depressed in, so your remote cam is actually turning it off not on? Incidentally, weren't there some of the TR range that had overdrive on 2nd, 3rd and 4th whereas 'our' cars only had the latter two? How did that work regarding an inhibitor? Colin Yes, my Tr5 had Over-drive on 2nd, 3rd and 4th, I think the early Tr6's are the same It's just additional Inhibitor switches I believe Regards Gary 1 Link to comment Share on other sites More sharing options...
johny Posted June 4 Report Share Posted June 4 Suppose OD cuts in and out between 2 and 3 which isnt very nice☹️ Link to comment Share on other sites More sharing options...
BrianY Posted June 4 Author Report Share Posted June 4 Hi everyone and thanks for taking the time to read this plea for help and respond. Its is actually very embarrassing because I am an idiot ! Your replies sent me out to the garage where I saw what I should have seen before. I was connecting the overdrive wiring to the reversing switch. I dont know how I did this and why I did not realise what I had done but if I hadn,t asked you and received your advice mentioning the rod and cam on the remote I would probably still be scratching my head. ! I probably now qualify for stupidest question of the month award. Doh Anyway when connected to the correct switch all seems to be working. Many thanks and apologies.>Brian>>> 2 Link to comment Share on other sites More sharing options...
Pete Lewis Posted June 5 Report Share Posted June 5 no worries pleased its all ok now in fact having an inhibitor in reverse would stop any OD damage as reversing with the D type engaged can wreck the one way clutch inside Pete Link to comment Share on other sites More sharing options...
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