Rex Posted March 1, 2018 Share Posted March 1, 2018 My speedometer works OK but it no longer lights up at night. I'm not sure how to get to the bulb and change it. I am as old as dirt and the last time I loosened the screws to lower it I could not see the back of it without SWMBO helping me with a mirror and a flashlight. Since she just had major back surgery I think I had better not ask for her help this time. I don't really want to disconnect the whole speedometer, since I have had calibration problems with it in the past. If this requires replacing the speedometer, I don't think it would be worth it since I almost never drive it at night. Thanks to anyone who can help. Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted March 1, 2018 Member Share Posted March 1, 2018 Assuming it's the lamp that has failed...Ordinary dash with separate round instruments? Illumination of all other instruments OK?The lampholder probably pulls out from the back of the instrument (towards the front of the car)... but I don't know all the variations on this. You can probably do that by feel alone, finding the lampholder by knowing that it has at least one wire attached to it and is probably off-centre of the instrument.But if you can't then you can release the instrument from the dash without disconnecting anything. Unless it's a very modern type you need to undo two knurled nuts using a finger and thumb in order to release the bracket which holds it against the dash. Something like this:http://st.hotrod.com/uploads/sites/21/2015/07/1965-chevrolet-c10-finger-tightening-nuts-onto-retaining-brackets.jpg?interpolation=lanczos-none&fit=around%7C596%3A372Then when you can see the back remove the lampholder from the instrument.Once the lampholder is free you can see and remove the lamp. I don't know how many types there are but we can identify it if you can find a number or post a picture of it here. Or you can take it to a shop.Assembly is the reverse...JonathanPS: You can get lamps of different colours and/ or replace them with LEDs... Link to comment Share on other sites More sharing options...
revilla Posted March 1, 2018 Share Posted March 1, 2018 Where are you located? Maybe some kind soul from your local area may be able and willing to pop round and give you a hand? Link to comment Share on other sites More sharing options...
SM25T Posted March 1, 2018 Share Posted March 1, 2018 Take a photo of the back of it with a mobile phone with flash on. As we discovered last week ... the latest speedo has a round collar that unscrews rather than a goalpost and knurled retainers on studs.. once you remove that rubber bung you should find a black bayonet fitting that you turn 1/8 turn and pull out. Then replace the tiny bulb in it. Easy job. You may even be able to do it without removing the speedo from the dash. If you do need to release it ... there may be enough slack in the cable to get the speedo through the dash without unplugging it. Otherwise ... No problem to unplug it ... you won't lose the calibration. Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted March 1, 2018 Member Share Posted March 1, 2018 The traditional bracket, from a Caterham rather than a Chevy pick-up:Jonathan Link to comment Share on other sites More sharing options...
Rex Posted March 1, 2018 Author Share Posted March 1, 2018 I live in the wilds of Central Pennsylvania--no other seveners around here that I know of. I forgot to say that my car is a 2002 SV with the original speedometer Link to comment Share on other sites More sharing options...
revilla Posted March 1, 2018 Share Posted March 1, 2018 OK - looking on a map there's a bit of water in the way for most people Link to comment Share on other sites More sharing options...
SM25T Posted March 2, 2018 Share Posted March 2, 2018 Same as I described then and the latest photo above. Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted March 2, 2018 Member Share Posted March 2, 2018 OK - looking on a map there's a bit of water in the way for most people De minimis non curat Rex?Jonathan Link to comment Share on other sites More sharing options...
Rex Posted March 2, 2018 Author Share Posted March 2, 2018 OK, I have loosened up the speedometer and there is a large round rubber bong and there is an electrical plug with three wires attached to it. I've pulled pretty hard on that but cannot get it to come out. I could try grabbing it with a small visegrip, but I sure don't want to break anything. There is no individual plug with one wire attached to it. I've pulled the rubber bung off and there is nothing in there but four little switches. Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted March 2, 2018 Member Share Posted March 2, 2018 ... and there is an electrical plug with three wires attached to it.Sounds a bit different from mine. Does it look like the picture in #5?And are there any other wires connected to the instrument anywhere?JonathanPS: I suspect that there's a little tongue to free the plug. Link to comment Share on other sites More sharing options...
SM25T Posted March 2, 2018 Share Posted March 2, 2018 Mine has 4 switches ... a potentiometer ... and a black bulb holder. There are no wires to it ... contacts connect to tracks on the pcb. Link to comment Share on other sites More sharing options...
Rex Posted March 3, 2018 Author Share Posted March 3, 2018 Yes--it looks like picture #5. Do I want to keep pulling on that switch? Link to comment Share on other sites More sharing options...
Rex Posted March 3, 2018 Author Share Posted March 3, 2018 What does the potentiometer look like? It's very hard for me to see in there, although I can feel the switches. If there's a black bulb holder in there, I can't see it. Maybe I should spray some WD40 on the three wired switch and try to pull it out and disconnect it with a vise grip so I can get the speedometer completely unhooked--then I should be able to see what I'm doing. Link to comment Share on other sites More sharing options...
SM25T Posted March 3, 2018 Share Posted March 3, 2018 I might have a photo in the archives ... potentiometer is a tiny PCB mounted unit. Have you removed the rubber grommet ... the lamp holder is the biggest thing in there .... twist it a few degrees anti clockwise and it should come out with the tiny bulb (286 ?) Link to comment Share on other sites More sharing options...
SM25T Posted March 3, 2018 Share Posted March 3, 2018 Found one on pistonheads site. This has 10 switches rather than my 4 ... But bulb holder is the same. See https://goo.gl/images/TtJWYY Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted March 3, 2018 Member Share Posted March 3, 2018 This is the one Ian found:http://www.hoonage.co.uk/images/Noble_Speedo.jpgand here's the diagram from Caerbont's instructions:This might not be the exact model but it's certainly the line I'd be taking. See Ian's comments in #15 about removing the lampholder once you've got the rubber cover off.JonathanPS: Caerbont instructions. Link to comment Share on other sites More sharing options...
Rex Posted March 3, 2018 Author Share Posted March 3, 2018 I finally got the speedometer out. The black bulbholder is missing. There is just a hole there, so I am assuming the bulb and holder must have fallen out at some point. Looked all over but can't find it. I am now heading to the autoparts with the speedometer and a picture of what the bulb and holder should look like. Thanks for all the help guys-I haven't given up. Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted March 3, 2018 Member Share Posted March 3, 2018 There is just a hole there, so I am assuming the bulb and holder must have fallen out at some point. Looked all over but can't find it.And there isn't a mysterious rattle from the instrument?If you can't find the missing bits locally you might be able to get them from one of the repairers in the UK.Jonathan Link to comment Share on other sites More sharing options...
SM25T Posted March 3, 2018 Share Posted March 3, 2018 Sure the bulb is a 286 ... It may be a generic bulb holder used in othe applications .... if you are lucky Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted May 27, 2018 Member Share Posted May 27, 2018 Solved?Jonathan Link to comment Share on other sites More sharing options...
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