Question about 2003 Toyota 4Runner
Check in the bonnet, you'll find the fuse box then follow the inscription on the fuse box cover.
Posted on Apr 11, 2009
The headlamp system in your Eldorado is controlled by the Body Control Module (BCM). Besides the light switch on the dash (which only provides grounds for certain BCM circuits) There are 10 different fuses, 5 relays, an ambient light sensor, a headlamp dimmer switch, the BCM and the Instrument Panel Cluster (IPC) involved in your headlamp circuits.
You asked about an easy way to check the switch...
The easiest way is to connect a scan tool and verify headlamp switch input at the BCM as you operate the switch and watch the BCM data.
I recommend that you begin this diagnosis by scanning your computer network for fault codes that may lead you to the cause of the problem. Please note that MOST generic OBD scanners (code readers) cannot access the BCM or IPC data.
Posted on Oct 30, 2011
Your vehicle’s computer system has self-testing capability. When the computer senses that there is a problem with some of the components it stores the correspondent trouble code(s) in its memory and lights up the "Check Engine" or "Service Engine Soon" light to tell you that there is a problem and you will need to have the car diagnosed and repaired.
Posted on Jan 31, 2009
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