Brighter, steadier lighting
Corroded switch contacts drop voltage before power reaches your lamps. With relays, current runs on a short, heavy-gauge path straight to the load, so your lights get the voltage they were designed for.
The PowerBlock wiring system
Reliable electrics for your British classic
Replace tired original wiring with heavy-gauge wire, modern fusing, and relays that take the load off your switches. Color-coded to the original Lucas scheme and built specifically for MGs, Triumphs, and other British cars.
- 7 relays
- 8 fuses
- 2 flashers
- 110 W headlamp capacity, each side
- Lucas color codes
Why upgrade your wiring
Most electrical trouble in a classic British car starts with age: worn switch contacts, undersized wire, and fusing that was marginal when the car was new. The PowerBlock system addresses each of these at the source.
Switches that last
Relays carry the heavy current, so your original switches only operate a small relay coil. Relays work with as little as 6–8 volts, so even worn switches keep doing their job, and you avoid buying costly, hard-to-fit OEM replacements.
Protection on every circuit
Eight correctly rated fuses protect the wiring throughout the car. Taking the load off old switches also keeps them from heating up, which in a worn switch can be enough to start a fire.
Made for your car
This is not a street-rod kit adapted with guesswork. The PowerBlock system is designed around the switches and layout your car already has, with every wire matched to the original Lucas color code.
Simple to service
Relays are standard parts. If one ever fails, a replacement costs around $5 and takes about 30 seconds to fit.
Clear, car-specific instructions
Every kit ships with a step-by-step manual written for your model. You can download the same manual before you buy and see exactly what the job involves.
Complete wiring harness
$790 postage paid
Everything you need to replace all of the wiring in your car. At its heart is the pre-wired PowerBlock, with seven relays, two flashers, and eight fuses. Heavy-gauge, high-quality wire, sized for the electrical load and the environment under a British car, connects the rest of the car to it.
Every kit now uses the compact PowerBlock at no extra charge.
What's in the kit
- Pre-wired PowerBlock with seven relays, two flashers, and eight fuses
- Heavy-gauge wire for the remainder of the car, color-coded to Lucas
- A complete set of terminals, connectors, and mounting screws
- Step-by-step instruction manual for your car
Relay-switched circuits
- High beams
- Low beams
- Horn
- Cooling fan
- Ignition
- Starter or overdrive (by application)
- Fuel pump
Lighter loads, such as the windshield wipers, draw little enough current that they don't need a relay.
Two PowerBlock versions
The standard PowerBlock includes a starter relay. Earlier Triumphs with an “A” type overdrive use a version with an overdrive relay instead. Tell us which you need when you order.
Why eight fuses
Eight fuses protect every circuit an MGB or Triumph TR needs. The 12-, 18-, and 21-fuse panels sold for street rods add circuits these cars don't have. Adding high-current accessories? Pair the harness with the auxiliary fuse panel or the driving light kit.
Headlight relay kit
$115 postage paid
Run high-output headlamps without rewiring the whole car. Two relays, one each for high and low beam, feed four lengths of pre-assembled, heavy-gauge wire. Each filament is wired and fused individually, so there is no splicing or daisy-chaining.
Fits any car. Not needed with the complete harness, which already handles headlamps up to 110 W each.
Auxiliary fuse panel
$90 postage paid
Four fuses and one relay for the accessories you add. Two circuits are always live, for items such as power door locks or a solenoid trunk release. The other two are switched by the relay, which you can wire to the ignition, for a power amplifier or power windows, or to a switch of your choice.
Fits any car, with or without the complete harness.
Driving light & auxiliary fuse kit
$115 postage paid
Add relay-switched driving lights and four extra fused circuits in one kit. Two circuits are always live and individually fused. Two more switch on with the ignition through a relay, on a common fuse.
Fits any car, with or without the complete harness.
Cars we wire
Complete harness kits are available for these models. Building something else, or need custom work? Contact us.
MG
- MGB and MGB GT, 1962–1980
- Late MGB V8 conversion
- MGC and MGC GT
- MG Midget Mk I, Mk II, Mk III, and 1500
- MG TD, TF, and MGA
Triumph
- TR2, TR3, TR3A, and TR3B
- TR4, TR4A, TR5, and TR250
- TR6, 1969–1976
- TR6 V8 conversion
- Spitfire Mk I–IV and 1500
- GT6 Mk I, Mk II, and Mk III
Austin-Healey, Sunbeam, Lotus
- Austin-Healey Sprite Mk I–IV
- Sunbeam Tiger and Alpine
- Lotus Elan
Coming soon
- Jaguar XK120–150
Read the manual before you buy
Every kit ships with a step-by-step instruction manual written for your car. The downloads below are the same manuals, so you can see exactly what the installation involves before you order.
Manuals are PDF files and open in any modern browser.
Free color wiring diagrams
Keeping your car stock? We have redrawn the factory wiring diagrams in color, with every wire printed in its correct color code and the layout rearranged so it is easy to follow.
The diagrams are drawn for 11 × 17 in. paper. If your printer can't handle that size, a local print shop can print just the pages for your car.
Color-coded wiring diagrams
- Triumph TR2 - TR3B (117KB)
- Triumph TR250 - TR6 (315KB)
- MGB (644KB)
Diagrams are drawn from the best information available, and specifications varied within model runs. Confirm that a diagram matches your car before working from it. More makes and models are in progress.
Expert help, before and after the sale
Questions about which kit fits, or about your installation? Call 616-889-9707 after 1:00 PM Eastern. Comprehensive technical support continues after your purchase.
Orders and general questions
Call 616-889-9707 or email sales@advanceautowire.com about an existing order or anything else.
Order your kit
Online: choose your options below and add each item to your cart. Checkout is through PayPal.
By mail: send a completed order form with a check or money order to:
Advance Auto-wire8277 Woodpark Dr
Byron Center, MI 49315
By phone: 1-616-889-9707
Not sure which kit you need? Call or email before you order and we'll help you choose.
From owners who've done the job