Why do my rear brake o r tail lights keep blowing in my Suzuki Khyber?

1. Overvoltage from Alternator Common in Old Khybers
If your alternator is overcharging, it can send too much voltage to your lights, especially when revving o r using accessories.

This excess voltage overheats the bulbs and drastically shortens their lifespan.

✅ Fix: Get your alternator and voltage regulator tested. Voltage at idle should be around 13.5–14.4V. Anything above that could be frying your bulbs.

2. Low-Quality o r Fake Bulbs
Cheap, locally made bulbs in Pakistan often don’t meet heat resistance o r voltage standards.

They might work for a while but will blow quickly with normal use.

✅ Fix: Use quality bulbs from brands like Philips, Osram, o r Narva — even locally available but genuine ones will last way longer.

3. Moisture Inside the Tail Light Assembly
If the tail light housing has a crack o r bad seal, water can get in — especially after rain o r car washes.

Moisture causes short circuits, corrosion, and can blow the bulb instantly.

✅ Fix: Inspect the light housing. If theres fogging o r water inside, reseal the unit using silicone o r replace the housing if cracked.

4. Loose o r Corroded Bulb Sockets
Over time, bulb sockets can get loose, corroded, o r burnt, causing poor contact.

This creates electrical arcing, which burns out bulbs quickly.

✅ Fix: Check the socket for signs of blackening o r rust. Clean it with electrical contact cleaner o r replace the socket if needed.

5. Bad Ground Connection
Tail lights rely on a good ground wire to complete the circuit. If the ground is weak, it causes voltage spikes that kill bulbs.

Its a subtle but very common issue in older cars like the Khyber.

✅ Fix: Trace the ground wire from the tail light to the body. Clean the connection point, remove rust, and tighten the bolt. Add an extra ground wire if needed.

6. Incorrect Bulb Wattage o r Type
Using a higher-wattage bulb o r the wrong type can generate too much heat, especially in the tight tail light housing.

It can also damage the reflector o r lens.

✅ Fix: Use the correct wattage usually 21/5W for dual-filament bulbs in Khyber. Avoid modified o r aftermarket LEDs unless theyre designed for 12V use.

7. Frequent On/Off Cycling City Driving o r Brake Riding
If you drive in heavy traffic, especially in Karachi o r Lahore, the brake lights are constantly in use.

More usage = more heat = shorter lifespan for weak bulbs.

✅ Fix: Consider upgrading to LED replacement bulbs — they last longer, generate less heat, and handle traffic conditions better.

🛠️ Quick Fix Checklist:
✅ Test voltage at battery and tail light wiring

✅ Use good-quality bulbs

✅ Clean o r replace sockets

✅ Check tail light seals for moisture

✅ Verify proper ground connections