Headlight Dimmer Switch: Inspection

WARNING: This page is about a different car, the 2008 Lexus IS F. However, it is still accessible from the selected car via links, so may be relevant.

INSPECT HEADLIGHT DIMMER SWITCH ASSEMBLY

Measure the resistance according to the value (s) in the tables below.

Standard Resistance:

Light Control Switch

STANDARD RESISTANCE SPECIFICATION

Tester Connection	Switch Condition	Specified Condition
12 (EL) -18 (T)	OFF	10 kΩ or higher
18 (T) - 19 (A)	OFF	10 kΩ or higher
19 (AUTO) - 20 (H)	OFF	10 kΩ or higher
12 (EL) - 18 (T)	TAIL	Below 1 Ω
12 (EL) - 18 (T)	HEAD	Below 1 Ω
18 (T) - 20 (H)	HEAD	Below 1 Ω
12 (EL) -19 (AUTO)	AUTO	Below 1 Ω.

Fig 1: Identifying Headlight Dimmer Switch Connector

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Dimmer Switch

STANDARD RESISTANCE SPECIFICATION

Tester Connection	Switch Condition	Specified Condition
11 (HU) -12 (EL)	LOW	10 kΩ or higher
11 (HU) -12 (EL)	HIGH	Below 1 Ω
12 (EL) -17 (HF)	HIGH FLASH	Below 1 Ω

Turn Signal Switch

STANDARD RESISTANCE SPECIFICATION

Tester Connection	Switch Condition	Specified Condition
12 (EL) -13 (TR)	Right turn	Below 1 Ω
12 (EL) - 13 (TR)	Neutral	10 kΩ or higher
12 (EL) - 15 (TL)	Neutral	10 kΩ or higher
12 (EL) - 15 (TL)	Left turn	Below 1 Ω

Fog Light Switch

STANDARD RESISTANCE SPECIFICATION

Tester Connection	Switch Condition	Specified Condition
3 (LF6) - 4 (BFG)	OFF	10 kΩ or higher
3 (LFG) - 4 (BFG)	ON	Below 1 Ω

If the result is not as specified, replace the headlight dimmer switch assembly.