There are several types of miniature lamps You need to learn how to test and replace them.
Bayonet style - S.C. Bayonet - The lamp on the left is a Single Contact (S C)That means there is one filament inside the light bulb. The index pins are at the same height. It does not matter what way you put it into the light socket assembly. - D.C. Index- The lamp on the left is a Double Contact (D C). There are two filaments and one is brighter then the other (tail lights & Brake Lights. Also the index pins are at different Heights so it will go into the light socket assembly only one way.
Bayonet style Notice the index pins on the light One is higher then the other
Bayonet style Single Contact Double Contact Double Contact Amber These all use the base of the lamp for Ground.
Wedge These are very common on side markers and brakes and tail lights. Come in all different sizes and candle power. Candle Power (cp) is the Brightness of the Lights or the light intensity. New Term is candela. One side is power the other side is ground.
Tail Light Lens Clear Turn signalAmber Turn signal May use a clear bulb behind a amber lens Must use a amber bulb behind a clear lens
To test a Plastic Wedge bulb Take Negative wire and clip it to both wires on one side Attach the Positive lead to the front side of the bulb
Flip the bulb over and attach the Positive lead to the other side See how we have wires on each side of the bulb (3157)
To test a Wedge bulb Hook up the wires to both sides of the bulbAnd it will turn on
Courtesy lamps Ridged Loop top End Cap bottom Festoon type
Instrument panel lights Some times we need to replace dash lights how do we do that?
Many different types of bulbs used in Instrument panels 194Used in a twist lock socket
#74 #37 #24 #194 #74 too small?..#194 too big? Could be a # 24 #74 & 37 are T1 3/4#24 are T2 3/4#194 are T3 1/4
Some dash lights use LEDs LED Lights come in several sizes NeoWedgeTwist Lock BAX series Pictures from
NeoWedge series Available in 3mm, 4mm, 5mm sizes To choose the correct bulb, measure the diameter of the base Type A (T3) 3mm base is 8mm= 5/16 Type B (T4) 4mm base is 10mm= 3/8 Type C (T5) 5mm base is 12mm= 15/32 Info from
NeoWedge series Remember when you test these light bulbs they are LEDs you must have the right Polarity in other words, you have to Hook up the power to the right side. A Diode is a one way check valve. If you hook it up backwards it will not work.