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RUK - Project Recommission 1972 'Dolomite' Auto http://forum.triumphdolomite.co.uk/viewtopic.php?t=32242 |
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Author: | James467 [ Wed Aug 02, 2017 11:37 am ] |
Post subject: | Re: RUK - Project Recommission 1972 'Dolomite' Auto |
Just moving aside to electrical wiring for a bit. I am going to relay the heated rear window with a 10 minute rear window timer relay (just a normal relay but with a 10 minute timer) 30 Amp rated and I have a nice momentary switch to replace the pull switch. The idea is that you press the switch and don't have to think about having to turn it off it automatically switches off when the ignition is switched off. The relay will sit behind the dash with the lights on warning buzzer. Tony (@MIG Welder) will probably know the answer to this! Question - does anyone know how many amps the hrw pulls when turned on? If not, I'll have to measure it. Looking at the existing switch there are two white and black wires running out to the rear window, do they run to each side of the rear window? Just need to make sure I'm getting the correct size wiring. Thanks! |
Author: | MIG Wielder [ Wed Aug 02, 2017 2:24 pm ] |
Post subject: | Re: RUK - Project Recommission 1972 'Dolomite' Auto |
Hi James, When I was doing the HRW on my 1977 1850 I measured a gnats over 10A but that was at 10.5V across the actual terminals of the HRW, with "13 and a bit volts" at the battery. So even "average" wiring drops quite a lot. It can be improved with thicker cable to the back, but even in Winter by the time I've de-iced the windscreen the rear vision is O.K. It's "adequate" rather than "astounding" in performance. Curious about the 2 black/ white tracer wires on the HRW switch. Is your HRW switch on the dash rather than down in the depths of the parcel shelf ? In which case I think that occurred from VA15,000 . Of the 2 black / white wires, on >15,000 one goes to the HRW bulb in the cluster, the other goes to the car's Nearside on the tag to the HRW. There is a bullet connector and colour change to plain black close to the connector in the boot high up on the LHS. The Offside connector goes down to earth. I'll have a look later when its stopped raining. [ Updated to correct locations 2/8/17 ] Tony. |
Author: | MIG Wielder [ Wed Aug 02, 2017 2:47 pm ] |
Post subject: | Re: RUK - Project Recommission 1972 'Dolomite' Auto |
Good pictures ! Is the odd wire hanging down also a white / black one ? Since there are 2 green wires and 2 black / white wires I wonder if B.L. doubled up the cables ( on early models) to get extra low cable resistance to the rear of the car. I'll check where the connector is at the back is in a mo. The black wire on the switch will be the bulb earth. Cheers for now, Tony. |
Author: | MIG Wielder [ Wed Aug 02, 2017 5:46 pm ] |
Post subject: | Re: RUK - Project Recommission 1972 'Dolomite' Auto |
There would be 2 alternative ways to wire this up. 1. Black, earth to pin 2. Black / white wires to HRW to pin 5. Existing green wire to pin 4 and link to pin 3 via a 15A in-line fuse. Momentary make switch from green wire on pin 4 to pin 1. This has the advantage of simplicity and since the existing green wire carries full HRW current it will be adequate for the new relay where it does the same. Alternatively ... 2. Black, earth to pin 2. Black / white wires to HRW to pin 5 . Existing green wire to pin 4. Momentary make switch from green wire on pin 4 to pin 1. Connect an in-line 15A fuse to the IGN accessory brown wire at the fuse box. Run a thick brown wire from this in-line fuse to pin 3 on the relay. Technically a better solution as the HRW current is kept out of the IGN ON fused circuit and the IGN switch so more volts at the HRW as well. As the relay control cannot operate until the ignition is ON you won't drain the battery unless there is a relay fault. The relay will drop out if the Ignition is turned off. If you need an "HRW ON" light indicator, connect between Pin 5 and Pin 2 on the relay. Fuses are always good but they do drop volts at high current. I have corrected my earlier post on which connection is which btw. Tony. |
Author: | James467 [ Wed Aug 02, 2017 7:25 pm ] |
Post subject: | Re: RUK - Project Recommission 1972 'Dolomite' Auto |
Thanks Tony, I like your second solution. Forgot to order a warning lamp - damn! |
Author: | Carledo [ Wed Aug 02, 2017 8:32 pm ] |
Post subject: | Re: RUK - Project Recommission 1972 'Dolomite' Auto |
The second white/black wire out of the switch goes to the warning light in the dash! Steve Edit, well at least it does on the later cars with the switch in the dash. And again, on later cars the second green goes on to power the rev counter, the seat belt warning light and oddly, the indicator flasher unit via the hazard light switch (I think this is to turn off the indicator unit if the hazards are deployed whilst the engine is running) I know all this because I have stripped my 78 Sprint main and dash looms and rejigged them to incorporate more fuses (14 in the main board in the original position, 6 of which are ignition controlled, plus 6 in an auxilliary board for headlights, spotlights and horn) and 10 relays. As a result, I have had to trace every single wire and a lot of them go in very counter intuitive directions! I'm not being as ambitious with the HRW as you are James, I've merely interrupted the output lead from the HRW switch in the area behind the glovebox and inserted a 30A relay into the circuit. Simple but effective! |
Author: | James467 [ Wed Aug 02, 2017 8:49 pm ] |
Post subject: | Re: RUK - Project Recommission 1972 'Dolomite' Auto |
Quote:
The second white/black wire out of the switch goes to the warning light in the dash!
Early car Steve, don't have a warning light on the dash.
Steve |
Author: | Carledo [ Wed Aug 02, 2017 9:07 pm ] |
Post subject: | Re: RUK - Project Recommission 1972 'Dolomite' Auto |
Quote: Quote:
The second white/black wire out of the switch goes to the warning light in the dash!
Early car Steve, don't have a warning light on the dash.
Steve Yeah, I worked that out, see edit above! I'll check my wiring diagrams tomorrow (they are down at the workshop) and find out where it DOES go! Incidentally, I have an early HRW switch in stock if you need one! Steve |
Author: | James467 [ Wed Aug 02, 2017 9:22 pm ] |
Post subject: | Re: RUK - Project Recommission 1972 'Dolomite' Auto |
Quote: I have an early HRW switch in stock if you need one!
Thanks for the offer, I just found a mom switch with an indicator light on it! Checked my wiring diagrams and I think you're right, I recon it loops into the tach then the hazard switch. I'll check when I go to wire it up. |
Author: | Carledo [ Wed Aug 02, 2017 9:32 pm ] |
Post subject: | Re: RUK - Project Recommission 1972 'Dolomite' Auto |
The more I get into Dolomite wiring, the more I realize JUST how marginal the original setup was! For example, the ignition controlled fuse (singular) The fuse says 35amps, but that is the surge blow rate, the continuous load rate is a mere 17 amps! And that has to run every fused, ignition controlled circuit on the car! On a cold wet morning, with HRW, wipers, brake lights, reverse lights on, as well as "normal" instrument and other minor functions, the poor thing must be stretched to it's limit! I wanted to wire the indicators separately and put ALL the instruments on 1 fuse (I know they are originally, but there IS only 1 fuse) To do this satisfactorily now, I will have to move the voltage stabiliser to behind the dash and may still need to share the indicators and HRW or install an extra fuse and lead, not sure I can be bothered at this stage! Steve |
Author: | Carledo [ Wed Aug 02, 2017 9:36 pm ] |
Post subject: | Re: RUK - Project Recommission 1972 'Dolomite' Auto |
Quote: Quote: I have an early HRW switch in stock if you need one!
Thanks for the offer, I just found a mom switch with an indicator light on it! Checked my wiring diagrams and I think you're right, I recon it loops into the tach then the hazard switch. I'll check when I go to wire it up. Steve |
Author: | James467 [ Wed Aug 02, 2017 9:41 pm ] |
Post subject: | Re: RUK - Project Recommission 1972 'Dolomite' Auto |
Completely agree, that's why I want to take the 'major load' stuff that I'll be using over the winter, lights, hrw etc... and put it onto a seperate circuit to relieve the original loom of at least some stress. I'd love to rewire the whole thing but I don't really have the time. I have learnt a huge amount about automotive wiring though whilst dining this. |
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