Wiring...I need help. :)

[BigB98]

Ok, there are things in life that we all know we're not good at. Wiring among other things is one of those things that has always given me problems. To that end, I have waiting far too long to finish that part of the project up and now I must get'r done.


I have an E-Z wiring harness, and I seemed to have misplaced the directions, though as I recall they weren't all that great and their website is a complete waste of time, so I have a few questions. I have separated the wires per the RCR instructions and I generally get things, but there's a few questions:

• What is the main line that comes from the battery and supplies the power to the fuse box? The heaviest guage line is the solonoid line, so I believe I run from the battery to the solonoid with heavy gauge and then from the solonoid I connect that main solonoid line to power the fuse box, right? If so, don't I need a switch on my panel that has power all of the time to flip which would activate the solonoid? Where does that power come from (do i just run a small line directly from the battery)?
• Would it be better just to run that solonoid line just directly to the fuse box from the battery?
• For the headlight and fan relays, where does the power come for those? Obviously I have a switch to turn flip the relay or whatever, but where does the full time power come from? (I think that's how it works)
• Any other wiring tips/tricks for a complete wiring bone head?

Thanks for any help.

 

[Chuck]

Attached is a chassis wiring diagram for our GT40. Hope this helps.

The 4 gauge between the solenoid and the battery as well as the 8 gauge lines were NOT supplied with the Painless wiring kit we used. We opted not to use the EZ wiring kit, although it should be functionally equivalent.

The relays were fed with the 8 gauge lines. Relays for the fuel pumps are located on the rear power board and relays for the headlight are located on the forward power board. The radiator fan relay is on the radiator bracket. Relays were kept as close to the device they feed as possible.

The 4 gauge wire also feeds the fuse box, which I located on the lower side of the dashboard.

The EZ wiring kit should include the wire that connectes the ignition switch to the starter solenoid. It is a smaller gauge wire since it carries only a enough current to activate the solenoid while the starter motor is fed by the 4 gauge wire.

Note the 50 amp chassis fuse. That should also be included in the EZ wire kit, but if not be sure to add it.

There are a lot more details and photos on my build blog, although the attached chassis wire diagram has not been posted before. If you need som more diagrams or pics, let me know.

There are many different ways to approach wiring. This way seems to have worked well. Hope this helps.

 

[Chuck]

For some reason the diagram I have attached did not upload. Here it is.

 

[Chuck]

Oops. Just noted an ambiguity. The relays and fuse box were not fed directly with the 8 gauge wire. The 8 gauge wire was secured to a juntion point on the aft and forward power boards. Smaller gauge wires were then fed from the relays to the junction point per the relay directions. The primary wire from the fuse box was connected to the forward 8 gauge junction point.

We used two terminal block from Jegs, part #555-10521, to provide the connect point for the 4 gauge to the relays and dash on the aft and forward power boards.

Obviously the 4 gauge bus line will be 'hot' all the time, so it will provide the power needed to activate the solenoid through the fuse box connection.

Hope this answers the questions.

 

[J. Salmon]

All I can offer is encouragement. I am flat dreading the wiring. So, steady on, you are not alone!

 

[Neal]

If you choose to use relays to power your headlights and horn be sure to fuse the main source which comes directly from the battery. I really hate to rely on crimped connections. It's really worth the time to solder and put some heat shrink insulation any crimped terminals. Be sure you have good grounds for your battery, dash, lights, etc. PM me if youneed help. I'd be happy to stop by.

 

[BigB98]

Thanks for the help, Chuck! Neal, I just might have to take you up on that visit! I'll see how I do this weekend and we'll go from there.

 

[Cliff Beer]

BigB if you feel like taking a look at another '40 local to you for a little visual help with the wiring as a guide then just let me know and you can come by and study my CAV. I'm in north Seattle, just north of Warren Mag park.

 

[BigB98]

Thanks Cliff. I need to hook up with you guys around here. I think i have things kinda worked out in my brain at the moment, but as soon as I look at the speghetti mess it'll probably all get dorked up.

 

[Ross Nicol]

I run large battery size cables directly from the battery to the starter with the positive lead through a cut off switch and the -ve terminal at the starter under a starter mounting bolt. Make sure the insulation is double on these large wires as a short will end in disaster. I had a close call recently when the wires shorted at the starter and melted the insulation to a point the bare wires were touching all the way between starter and battery. It is a good idea to keep these wires as short as possible and if you run them alongside each other use heater hose to further insulate the positive lead. I crimp an extra earth lead (6mm) with the Battery negative terminal and bolt the other end to the chassis.This is the main earth to the chassis and is important since all circuits other than the starter use this wire as a return path.I then run 6mm (probably equivalent to your 8 gauge) red wires through fuses to relays for fans,headlights,engine management etc. I also feed the ignition switch, and dash control circuits from this point too.
I then set up 3 rows of 10 way fuse banks and feed all 10 terminals on one side from 1/ ignition switch acc position
2/ ignition switch on position
3/ Direct feed bypassing ignition switch

I then decide which fused supply best suits the circuit I want to power and wire to that circuit accordingly. The painless fuse blocks actually do the feeds for you and theoretically make the job easier but I think your understanding of the circuits is made more difficult.
Probably the most difficult area for home electrics DIYer to understand is earthing.You must provide suitably sized cable for earth returns ie the earth lead must carry the same current from a fuel pump as the hot lead carried to it.Keep the earth wires short and clean the area where the terminal makes contact with the chassis. It's not my main job but I enjoy wiring performance cars. My advice is to plan the job and go over and over the plan to make sure you haven't missed anything taking it slowly enough to check everything as you do it and after you've done it. Remember we all make mistakes but you need to catch them early so you can fix them at an early point. I don't suppose you'd call a Range Rover a performance car but I've just helped my 78 year old part time employee to replace the electric brake unit in his RR. You can probably imagine the terrible state of the electrics in this vehicle after multiple owners have had a go at it. Suffice to say the brakes on his Caravan now work properly instead of going off and on in sympathy with the turn signals.
Ross

 

[Iain]

Ross
I am concerned by your suggestion that the wiring on a British car is less than perfect, have some respect , what is worse is that you have chosen the flagship of the aspiring middle classes to air your opinion, I very much doubt that you will receive an invitation to either Goodwood or Henley. Shame on you !

Iain

 

[CraigB]

I am concerned by your suggestion that the wiring on a British car is less than perfect, have some respect , what is worse is that you have chosen the flagship of the aspiring middle classes to air your opinion, I very much doubt that you will receive an invitation to either Goodwood or Henley. Shame on you !

Range Rover may be the darling of the aspiring middle classes (those that don't drive Chrysler Voyagers or Mitsubishi Warriors anyway), but it's not exactly the most British car on the planet. I think the Germans (BMW) have just sold it off to India (Tata)

Craig

 

[CraigB]

The shortlist for "British cars" is getting shorter by the day!

Rover/MG - what's left - Chinese
Bently - German
Rolls Royce - German
Vauxhall -GM
TVR - Russian
Aston Martin - British run with Bahrain money and a minority share by Ford.
McLaren - 40% German, 40% Bahrain.
Range Rover - Indian
Jaguar - Indian
Mini -German
Lotus - Indonesian?


I think this probably leaves the likes of Mirage. Tornado, MDA and Southern as leading British car builders! (or I might be slightly biased there ; - I think there are one or two Cobra companies as well)

Cheers

Craig

 

[Jack]

As far as I know Morgan is the only one left that is truly a British manufacturer.

 

[Keith]

I took a slightly different approach to the power supply wires on my car. The EZ harness supplied by RCR actually seemed well suited to this application so it was used with the modifications as described.
I purchased three "Maxi Fuse" holders off e-bay I soldered the three ends of the three holders to a large copper lug that I got from Home Depot and attached it to the large cable lug on the starter (the lug where the battery cable attaches). The first fuse holder was fitted with an 80 amp fuse and an 8 gauge wire was routed to the alternator to handle the output of the alternator. The second fuse holder was fitted with a 40 amp fuse and a 8 gauge wire (overkill for this application) and was run forward to supply power to the cooling fan relays and the driving light relay. The third fuse holder was fitted with a 60 amp fuse and an 8 gauge wire was run forward to the fuse block area where I soldered both the "solenoid power" wire and the "alternator power" on the EZ harness to it for the power supply to everything else in the car (the alternator wire and the solenoid wire are hooked up to the same power distribution bar in the fuse block so you could hook up one or both and have the same outcome). In doing it this way the alternator power wire is very short and does not have to get routed all the way to the front and back (it also provides for fuse protection) and it keeps the high power load devices like the fans and the driving lights out of the fuse block. Everything worked as planned so I am happy with my decision to do it this way.
My only real wiring issue was figuring out how to make the hazard lights work correctly with the turn signals; but that is a story for another day.........
Keith

 

[Chuck]

Keith:

Coming up with a wiring plan for the flashers / blinkers was the funnest part of the wiring! Okay, so I am a bit off. The idea of using relays to switch the ground circuit rather than the power circuit occurred to me in the shower one monring. Funny how the mind works.

Attached is wiring diagram. Used three relays, turn indicator switch, and a four way flasher switch (Lucas switches). The four way flasher will over ride the turn indicator, if both are turned on. The flashers will work with the ignition off, but the turn indicators only work with the ingition on. Just like a 'real' car!

There are switches out there that will accomplish these objectives without relays, but we wanted to use the Lucas switches, hence the need for the relays.

Let us know how you wired yours! I am curious to know if there is an easier way using the Lucas switches.

Chuck

 

[Brian Kissel]

Although not for a GT40, here is a very nice schematic for a Ultima. The nice thing about this is you can remove differant layers and only show the circuits you want. I like being able to blow it up so blind people like me can see it.

Ultima_wiring_diagram(HiRes).pdf

Regards Brian

 

[Keith]

Chuck,
Yes, I used the Lucas switches also. As the rear lamps supplied with the RCR have three bulbs (tail/park, Turn, and brake) I was able to use the "third brake" wire for the brake bulbs so no brake light crossover (like in a column mounted switch) was necessary.
I hooked up the "turn signal flasher output wire" to the lucas switch and the "left turn" and "right turn" to the spades on the lucas switch. The left and right turnsignal indicator wires went to the indicator lamps in the dash. Everything worked fine......

The problem was the hazard flashers as I could not find a switch or a relay that would isolate the flashers (two isolated output spades connecting to one "pull" input spade from the hazard flasher). I solved it by getting two "universal relays" from the local Auto Zone and powering them with one of the unused "unswitched" power circuits (I think it was the dome light cricuit). I used one of the Lucas "single pull single throw" switches to activate it through the relay ground circuit. The relay "power in" spades were connected to the output side of the hazard flasher and one relay output was connected to the left turn and the other relay output was connected to the right turn. This way the turnsignals would work only when the key is on and the hazards work with the key off with the relays isolating the turn signal circuits.
It took me a good day of pondering to get it figured out...............but it works!
Keith

 

[Chuck]

Keith: If I am understanding your description, it sounds like we came up with essentialy the same system: relays and switching the ground circuit to activate the hazard flasher. Cool.

 

[Bill Tracy]

As far as I know Morgan is the only one left that is truly a British manufacturer.

Don't forget Ginetta!

BT