Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Ballast Wire Check
1980 Triumph SpitfireSECTION Ballast Wire Check
- On most models, such as the TR7, a pink/white ballast resistance wire is built into the wiring harness leading to the ignition coil. The wire causes a voltage drop so the 12-volt supply may be used to power the 6-volt ignition coil. During engine start, the resistor is bypassed to apply 12 volts reduced by starter load directly to the coil.
- To check resistor wire, turn ignition switch "OFF" and attach ohmmeter leads to each end of pink/white wire. Resistance should be 1.3-1.5 ohms. If not, replace ballast resistor wire.
RENDER: 1.0x
NO RELATED
Recommended Tools & Savings
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Affiliate disclosure: We may earn a commission at no extra cost to you.
When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.