tr7triumph.com

I have been looking for a long time now at replacing the bulbs in my dash to nice bright LED’s. I have done a bit of research and have ordered the following set of bulbs.

My thought is that if they are wrong, it is only 3 pounds, so not too much lost.

http://www.ebay.com.au/itm/20-x-T10-194-168-2825-5-x-5050-SMD-LED-Green-Super-Bright-Car-Lights-Lamp-Bulb-/160982226419?hash=item257b49d5f3:m:mSvjFUSYHQBd6SKcGLJ8KiQ

Phil, Those LEDs are same / similar to the LEDs that I used to convert my dash. They certainly improve the visibility of dash instruments etc. Indeed you may find that they are a little too bright compared to the standard incandescent bulbs.

LEDS do not dim well with the standard TR7 dimmer unit (rheostat) they require a pulse width modulation electronic dimmer. What is required is a common earth or negative configuration. These are available but not readily identifiable until after delivery. The topic has been covered elsewhere in this forum series and I have also provided some input on the "triumph experience' website where there are several lengthy discussion threads with photos, part numbers etc of the correct design dimmer. Suggest you search for LED dash under the spitfire & GT6 forum on the "triumph experience" site. There are many of these available online (search the bay) for very reasonable prices but not all are suitable, most actually use what is known as a common positive configuration, ie both 12v positive input and positive output terminal are connected together - the variable output is actually the negative line. When connected into the TR7 dash circuit this configuration effectively supplies a constant 12v supply to the dash lamps as the negative for the dash lamps is connected directly to the vehicle earth/ground.
If I find the details in my archives I will try to repost text on this site - may take a few days though.

You can change out the bulbs to LED from the back of the dash instrument assembly, but be very careful as the flexible printed wiring on instrument assembly is quite fragile after many years and not uncommon for the printed tracks to lift or break away from flexible backing. I would suggest you consider taking the whole instrument assembly out (only a few screws, plugs & speedo cable - refer to the manual) and consider access from the front (remove the clear panel and then remove the speedo & tacho instruments. This will allow you to clean out years of dust and remove the green diffuser lens which is used to provide green light from the incandescent bulbs. The diffuser is not necessary with LEDs and provide a little more space. Also in doing this you can use a small amount of aluminium foil to improve the shielding around the indicator light shrouds. This is fairly obvious once you have it open. Be careful you don't lose pieces as most of the lighting filter / lens labels are loose fitting.
If you want to replace the other indicator/warning light bulbs with LEDs you should use the leds which emit light from the end, also in T10 plus 2 X T5 size. Select LED colour to match the indicator ie red LED for a red indicator. White LEDS dont work as well behind a coloured filter.
Note do not replace the alternator/ignition warning light with an LED bulb. Following is a an abbreviated summary of why. LEDs are one way solid state devices and the alternator/ignition circuit requires a conventional bulb for the alternator circuit to function correctly. When ign key is turned on, 12v is supplied to ignition bulb (effectively a resistor with no specific polarity) to earth through alternator excitation terminal, hence bulb lights up. Once started the alternator supplies a counter 12v from excitation terminal - effectively 12v both sides of bulb (no voltage differential) hence bulb no longer illuminated. If the alternator loses its excitation output ie Alternator stops working, the counter 12v not present therefore bulb will light indicating the failure. LED does not allow for this 2 way current flow.

Sorry this may be a little lengthy. Good luck. Rgds, Daryl M

I agree that using white LED's with the green lenses does not work, unless you want blue lighting. I changed mine some years ago and found this, will change them again one day!

I also found it is common for the base plastic of the housing (under the printed circuit) to become soft and depressed with the heat of the standard bulbs giving poor contact of the bayonet holder to the PC track. I cured this by putting a small snippet of household draught excluder foam under the PC stuck to the housing. This provides a springy cushion to hold the track against the bayonet contact.

I've replaced the indicator and warning lights down the middle with white LED's (not the Alt light) it's made them a lot brighter but I had to lightly sand the surface of the LED to help the difuse the lighting. I plan to change them to a warmer colour as it's made the red lights a bit pinky.

The backlighting I've kept as incandescent bulbs so the dimmer works, I've just fitted slightly higher wattage so I have the option of turning them up if needed.

Phil et al,
As mentioned in my previous post re LEDs, try typing the following web address into browser for the info and some pictures on the dimming LEDs:
http://www.triumphexp.com/phorum/read.p ... 661,page=4

Rgds DM

Just remember the brighter the dash lights the less you can see outside so you need brighter headlights to compensate (a vicious circle). If you do mostly city driving at night you may need brighter dash lights to match the brightly lit street lights but for out in the country you need to be able to turn them down so you can see better from the headlights. If using incandescent dash lights you need all connections clean including bulbs, bulb holders, copper lands on circuit (Brasso works well). The higher the resistance, the less bright the light (the basis of the dimmer), the higher the heat generated (the basis of the incandescent bulb). This was illustrated to me the other day where one of the connectors to one of the door switches on my micro wave oven corroded and melted the wire (and insulation) while the smaller wire also connected to the same spot which wasn't corroded was fine. Putting a new connector on and soldering the two wires fixed the problem and everything is fine.

I would certainly caution against fitting higher wattage than standard due to the risk of melting the housing, lenses and adjacent area. supercass

On the earlier version of this forum, there was a chap the other side of the North Sea who went by the moniker Odds. He arranged some high quality green LED's for a few members in 2008 which have worked well on my 7 ever since. They run without the original green plastic covers and provide a better quality light than the original bulbs - there is no glare, but the visibility in half light conditions is much improved. Surprisingly the dimmer still has some effect and does reduce the output, if necessary, though in my experience this has never been necessary.

Thanks for the comments guys. I do intend to move the green lens when I add these bulbs as they are also green and there is no need for them. From what I could see they were the same as ones recommended for the 7 on other sites. Was there some indication that these ones are higher voltage than the ones we have in already or are you saying that you just would not fit higher voltage ones?

Do like the idea of the dimmer for the led's though.

I researched LED's a few years ago and produced a series of detailed articles for the South African Sabrina. The TR Drivers club included an edited version in their Magazine a few issues ago. This included all the required LED bulb specs and their suppliers most importantly the need for an LED flasher relay. My 8's dash and tail lights are great but I discovered something that nobody mentions and that is power. The combine LED's in the rear lights reduces the power through the harness by as much as 90% think of the increased life in your now ancient harness. As to colour the answer is simple a coloured lens only allows about 20% of the light of a colourless bulb to pass through it but it allows about 80% of the light from a bulb of the same colour as the lens to pass through it. Hence keep dash board led's the same colour as their lens. Warning DO NOT replace the ignition bulb with an LED or your car won't start.
If you want the detailed article then send me your E-Mail address since it is too long for this Forum.

Sautie

What did you do about the hazard flasher relay? For the indicators the aftermarket electronic flasher works fine with both LED and standard bulbs, but I wasn't able to track down a replacement for the hazard flasfer relay (which has two separate sets of contacts)

I fitted 50 watt metal cased resistors in parallel with the LED bulbs to overcome this problem, but its not the ideal soloution.

Cheers

Howard

I too will be looking at replacing as many of the bulbs as I can with LED’s and was also considering the indicators the after-market electronic flasher unit that can be brought for a very reasonable price.

Sautie wrote:I researched LED's a few years ago and produced a series of detailed articles for the South African Sabrina. The TR Drivers club included an edited version in their Magazine a few issues ago. This included all the required LED bulb specs and their suppliers most importantly the need for an LED flasher relay. My 8's dash and tail lights are great but I discovered something that nobody mentions and that is power. The combine LED's in the rear lights reduces the power through the harness by as much as 90% think of the increased life in your now ancient harness. As to colour the answer is simple a coloured lens only allows about 20% of the light of a colourless bulb to pass through it but it allows about 80% of the light from a bulb of the same colour as the lens to pass through it. Hence keep dash board led's the same colour as their lens. Warning DO NOT replace the ignition bulb with an LED or your car won't start.
If you want the detailed article then send me your E-Mail address since it is too long for this Forum.

Cool, thanks for that; I have sent you a PM with me email address. That is what I am looking for as tracking down the bulbs can be a bit of a pain. You could always add a post on the parts section.

All these queries are answered in my article.If you fit a solid state relay CF13 GL02 from www.squaredeals-ltd.co.uk you will not need to fit shunt resistances merely replace your existing flasher and hazard unit with this one(it will need a separate earth) and heh presto. My USA "cruising lights" I have wired up as indicators and they run and work with the LEDs. All LED bulb specs are listed in my article and they fit straight in without any cutting or shutting. So send me your E-Mail Address and I will send the full article.

I must admit to being perplexed re the fitting of an electronic relay. Some are adjustable and presumably others are set to flash at a set rate. Given that does the unit actually detect if a bulb or resistor has failed, if so how? Also if you fit a resistor am I right in thinking that a failure warning system detects resistor failure and not led failure so it would thus be possible to have an led bulb fail but not the resistor and not be made aware. Also doesn't the fitting of a resistor negate to some degree the benefit of LEDs reducing the load on the circuit? Sorry to show my ignorance but I would be grateful if someone could clarify this for me.
supercass

If you fit a relay that just flashes at a fixed rate regardless of load then you will loose the handy feature where it flashes faster so you know a bulb has blown/bad connection.

If you keep the original type relay then you will need to add resistors in parallel with your new LED lights to make the load on the relay the same as if you were using incandescent bulbs or it will flash too fast, by keeping the load the same you don't gain anything from changing to LED's.

My advice is stick to old fashioned incandescent bulbs in your indicators and fit LED's elsewhere (sidelights, taillights, number plate lights, brake lights etc) afterall the reduction in load on your car's electrical system for the indicators is negligible if you consider how often they are actually lit for.