Relays, Rectifiers And Voltage Regulators
This collection covers essential auto-electrical charging and control components, including alternator voltage regulators, alternator rectifiers (diode packs), and 12V/24V automotive relays. Use it to find the correct part by OE number, plug type, pin layout, amperage, and application.
What You Will Find In This Collection
- Alternator Voltage Regulators: Controls charging output to protect the battery and electrical system.
- Alternator Rectifiers (Diode Packs): Converts alternator AC current to DC current used by the vehicle.
- Automotive Relays: 4 pin and 5 pin relays for switching high-load circuits safely and reliably.
How To Choose The Correct Part
- Match the OE number: The fastest way to confirm compatibility when available.
- Confirm voltage: 12V passenger vehicles vs 24V commercial and truck applications.
- Check plug type and pin layout: 2 pin, 3 pin, 4 pin, stud terminals, and regulator plug variants.
- Relays: Confirm 4 pin or 5 pin changeover, amperage rating (e.g. 30A), and whether a holder is required.
- Rectifiers: Confirm alternator brand/type and mounting style to avoid mismatch.
Common Symptoms These Parts Can Fix
- Battery light on the dash, undercharging or overcharging
- Flat battery, dim lights, unstable voltage, intermittent electrical faults
- No-charge condition caused by rectifier or regulator failure
- Fans, fuel pump, lights, or accessories not switching correctly due to relay issues
Ordering And Fitment Support
If you are unsure, match by OE number, alternator details, plug type, and clear photos of the old unit. We deliver across South Africa, including Cape Town, Johannesburg, Durban, Pretoria, Gqeberha, and surrounding areas.
FAQ
Do I need a regulator or a full alternator?
If the alternator is mechanically sound and bearings are quiet, a regulator or rectifier repair often restores charging at a lower cost.
Confirm by test results and matching the correct plug type and OE number.
What is the difference between a rectifier and a regulator?
A rectifier (diode pack) converts AC to DC. A regulator controls the alternator output voltage to prevent overcharging and undercharging.
How do I choose the correct relay?
Confirm 12V or 24V, 4 pin or 5 pin, the amperage rating (commonly 30A), and whether you need a relay holder. Match the circuit function
and terminal layout.
Will a 2 pin regulator replace a 3 pin regulator?
Not usually. Pin count and plug type must match, and internal control logic can differ. Always match the plug type and OE reference where possible.
Can these parts cause a battery to go flat?
Yes. Undercharging from a failed regulator/rectifier can leave the battery discharged. Some electrical faults can also cause parasitic draw,
so testing is recommended.