The dimmer switch on my 89' pontiac Firebird won't switch my headlights from dim to bright. It doesn't click when I press on it either. I'm guessing there is a part missing, but I'm not to sure. How can I fix this?

. The illumination is controlled by the BCM - body control module .
Interior Lamps Dimming
This group includes lamps which may dim. This group may use a combination of vacuum fluorescent (VF) illumination and incandescent lamps.
• HVAC control module, head assembly
• Rear HVAC control module, head assembly
• Radio
• Rear seat Audio
• The instrument panel cluster (IPC)
• The PRNDL lamp, with the exception of the current gear select position
• Power window switches
• Various switches
When the ignition switch is turned to the ON position, the VF display, radio, turns ON at maximum brightness. When the park lamps are ON, all incandescent back lighting turn ON at the dimming level indicated by the instrument panel (I/P) dimmer switch. At the same time all VF displays dim to match the indicated dimming level. When the headlamp switch is placed in the PARK position, the park lamp supply voltage circuit provides an input to the body control module (BCM). The BCM then supplies voltage to the I/P dimmer switch through the I/P dimming lamps control circuit. The setting of the I/P dimmer switch determines the amount of voltage that the I/P dimmer switch supplies to the BCM through the I/P dimming lamps low reference circuit. The BCM then sends a pulse width modulation (PWM) voltage to all the interior lamps. All the VF and incandescent back lighting lamps are provided a specific voltage and are then grounded. When the headlight switch is turned to the park lamp or headlamp position, all incandescent back lighting turn ON at the dimming level indicated by the I/P dimmer switch. When the I/P dimmer switch is moved from MIN to MAX, all VF displays, as well as all incandescent back lighting respond from minimum intensity to maximum brightness in response to the I/P dimmer switch.


Do you know what DTC'S - diagnostic trouble codes are ? Codes set in the BCM
DTC B2610 00: Passenger Compartment Dimming 1 Circuit
DTC B2615 00: Passenger Compartment Dimming 2 Circuit
DTC B2652 00: Passenger Compartment Dimming 3
Circuit/System Description
The instrument panel (I/P) lamp dimmer switch is used to increase and decrease the brightness of the interior backlighting components. The I/P dimmer switch provides a voltage signal that will increase as the brightness of the lights are increased and decrease as the brightness of the lights are decreased. The body control module (BCM) provides a low reference signal and a B+ voltage reference to the I/P dimmer switch. When the I/P dimmer switch is placed in the desired position, the dimmed voltage setting is applied from the I/P dimmer switch through the I/P dimmer switch signal circuit to the BCM. The BCM interprets the signal and applies the dimmed voltage to the I/P lamps supply voltage circuit and the interior backlighting components dim to the requested level. Ground for the I/P dimmer switch is provided at G201.

sunroof fuse 1 20amp / power windows - circuit breaker 25 amp
both of these are located in the instrument panel fuse box .

That is a common problem, the switch needs changing if the high and low beams do work, the only problem is that it's an expensive part to replace, try a local wrecking yard they should have a bunch of suitable replacements at a reduced price.

you could have a dimmer switch problem that may need an adjustment or replacement.do you hear the switch click when you try to change from high to low,if not than these could be the problem.the switch is located on the top of the steering colume and the base of the colume under the dash.if you work the dimmer switch on the colume and put your hand on the colume under the dash you should be able to feel the rod that pushes on the switch.follow the rod down and it will go to the dimmer switch.there are 2 5/16 bolts that hold it in place that if you loosen them and push the switch up towards the steering wheel it will move it so the rod won`t have to move as far to change from low to high.if this is not the problem and you don`t hear a click then its usually a switch replacement.

Is it equipped with auto dimmer sensor? When it sees oncoming headlights it would dim the brights automatically.

It sound more like the ground wire for the headlight is bad or the plug is corroded and not making a good connection. Lee

I guess that means replacing the bulbs didn't work? The only other thing might be the dimmer switch. Its located on the bottom of the steering column, about halfway down fron the steering wheel.

heyyyyaaa.i have a 89 firebird t/a ..niceee but have a problem[ the module on the firewall that controls your headlights to raise up n down doesn't work..headlites come on..but manually raise n lower the lites bc i drive it at nite n day ..lol..all the time now..chevy place is asking 300.00 for it.i paid enough for the car as is..looking for anyone for help bc i give you 150 for that module]..its size..flat with two connectors(rghtside)(leftside) about 1 or two thick n abt4/5 inches tall on the drivers side firewall..call me anytime 4436530761 bc im gtn tired manually working the headlights..joe

check the alternator charge level .
check the battery + and - are not lossing
if nothing then you have wiring short

Check at the headlight sockets for a bad ground.

To all, check your dim bulbs. Make sure they aren't burnt out. If they aren't, time to see if your dimmer/turn signal switch is the problem. For the switch, take it to a mechanic or see if someone else will help ya. Wiring isn't my best subject in autos.