When I brake guages fluctuate

Ignition switch. This will cause all those problems. Turn it off, the gauges go blank/dead. Leave the lights on and remove the key, what happens..

most cars, the brake light comes on for many reasons.
4 or more, ebrake suck on, low fluild levels and catastropic brake failure.
key on , the lamps are in test mode. ebrake off , lamp off or its and error.
now temperature.
is it real> ? can fail in many ways
1:loose wire at sender
2: air pocket below, thermostat (look down rad cap hole dead cold
is the RAD full and burped of all air. ? if not bingo)
the temp guage hates air, it can not reAd Air temps,

If all voltages checked ok,then most probably its faulty instrument cluster board on which gauges are connected.Yes if cluster circuit board looks ok,then also it can be faulty.Somewhere there is minute short or burn on board then such prolem arises.
Also check the fuse box.One under hood and other under dash.Inspect each and every fuse and see if all are fine or not.
---------------For more troubleshooting on these cluster gauges i suggest you to refer the list of help links mentioned below.Its step by step instructions will help you to confirm the exact cause of problem in these conditions:---------
Click the link below:------

2004 Toyota Tundra: Oil Gauge and Temp Gauge Not Working?

http://howtobyme.blogspot.in/2012/05/2004-toyota-tundra-oil-gauge-and-temp.html

--------------

2005 Lexus SC430: Fuel Door, Dome light and Fuel Gauge Fuse Location?

http://howtobyme.blogspot.in/2012/05/2005-lexus-sc430-fuel-door-will-not.html
----------

Toyota 4Runner: Temperature Gauge Sensor

http://technoanswers.blogspot.in/2012/04/toyota-4runner-temperature-gauge-sensor.html
------------

Temperature gauge sits over half way mark?

http://schematicsdiagram.blogspot.in/2012/04/temperature-gauge-sits-over-half-way.html

---------------

Heater blows intermittently and temp gauge goes erratic?

http://technoanswers.blogspot.com/2012/01/heater-blows-intermittently-and-temp.html

----------

Temperature gauge does not move and no heat when heater is ON?

http://technoanswers.blogspot.com/2012/01/temperature-gauge-does-not-move-and-no.html

-----------

2003 Pontiac Grand Prix: Erratic Fuel Gauge?

http://technoanswers.blogspot.in/2012/06/2003-pontiac-grand-prix-erratic-fuel.html

-----------

Temperature gauge keeps fluctuating up and down close to red?

http://technoanswers.blogspot.com/2012/01/temperature-gauge-keeps-fluctuating-up.html

-------------

Temperature gauge on the dash quit working on Pontiac Grand Prix?

http://technoanswers.blogspot.com/2012/01/temperature-gauge-on-dash-quit-working.html

---------------

Fuel gauge jumps from empty to full?

http://schematicsdiagram.blogspot.com/2011/12/fuel-gauge-jumps-from-empty-to-full.html

--------------

Gas gauge stuck on empty on 2002 Mercedes Benz 240c?

http://repairhelpcenter.blogspot.in/2012/02/gas-gauge-stuck-on-empty-on-2002.html
---------------

• Oldsmobile Temperature Gauge Lamp Switch?

-----------------

Fuel gauge drops to Empty?

http://technoanswers.blogspot.com/2012/01/fuel-gauge-drops-to-empty.html

----------------

Dodge neon gauges not working?

http://technoanswers.blogspot.in/2012/02/dodge-neon-gauges-not-working.html

------------

Temperature gauge went up?

http://schematicsdiagram.blogspot.com/2011/12/temperature-gauge-went-up.html

------------

Temperature gauge stays At cold on jaguar?

http://technoanswers.blogspot.in/2012/02/temperature-gauge-stays-at-cold-on.html
-----------

How to replace Instrument panel and dashboard on Toyota car?

http://repairhelpcenter.blogspot.in/2012/02/how-to-replace-instrument-panel-and.html

-----------

How to remove instrument panel on Chevrolet car?

http://technoanswers.blogspot.in/2012/02/how-to-remove-instrument-panel-on.html

-----------

How to remove control panel on Buick regal?

http://howtobyme.blogspot.in/2012/02/how-to-remove-control-panel-on-buick.html
---------------
These details will help.Thanks.

If all voltages checked ok, then most probably its faulty instrument cluster board on which gauges are connected. Yes if cluster circuit board looks ok, then also it can be faulty. Somewhere there is minute short or burn on board then such problem arises.

Also check the fuse box. One under hood and other under dash.

Inspect each and every fuse and see if all are fine or not.

---------------

For more troubleshooting on these cluster gauges I suggest you to refer the list of help links mentioned below. Its step by step instructions will help you to confirm the exact cause of problem in these conditions: ---------

Click the link below: ------

2004 Toyota Tundra: Oil Gauge and Temp Gauge Not Working?

http://howtobyme.blogspot.in/2012/05/2004-toyota-tundra-oil-gauge-and-temp.html

--------------

2005 Lexus SC430: Fuel Door, Dome light and Fuel Gauge Fuse Location?

http://howtobyme.blogspot.in/2012/05/2005-lexus-sc430-fuel-door-will-not.html

----------

Toyota 4Runner: Temperature Gauge Sensor

http://technoanswers.blogspot.in/2012/04/toyota-4runner-temperature-gauge-sensor.html

------------

Temperature gauge sits over half way mark?

http://schematicsdiagram.blogspot.in/2012/04/temperature-gauge-sits-over-half-way.html

---------------

Heater blows intermittently and temp gauge goes erratic?

http://technoanswers.blogspot.com/2012/01/heater-blows-intermittently-and-temp.html

----------

Temperature gauge does not move and no heat when heater is ON?

http://technoanswers.blogspot.com/2012/01/temperature-gauge-does-not-move-and-no.html

-----------

2003 Pontiac Grand Prix: Erratic Fuel Gauge?

http://technoanswers.blogspot.in/2012/06/2003-pontiac-grand-prix-erratic-fuel.html

-----------

Temperature gauge keeps fluctuating up and down close to red?

http://technoanswers.blogspot.com/2012/01/temperature-gauge-keeps-fluctuating-up.html

-------------

Temperature gauge on the dash quit working on Pontiac Grand Prix?

http://technoanswers.blogspot.com/2012/01/temperature-gauge-on-dash-quit-working.html

---------------

Fuel gauge jumps from empty to full?

http://schematicsdiagram.blogspot.com/2011/12/fuel-gauge-jumps-from-empty-to-full.html

--------------

Gas gauge stuck on empty on 2002 Mercedes Benz 240c?

http://repairhelpcenter.blogspot.in/2012/02/gas-gauge-stuck-on-empty-on-2002.html

---------------

• Oldsmobile Temperature Gauge Lamp Switch?

-----------------

Fuel gauge drops to Empty?

http://technoanswers.blogspot.com/2012/01/fuel-gauge-drops-to-empty.html

----------------

Dodge neon gauges not working?

http://technoanswers.blogspot.in/2012/02/dodge-neon-gauges-not-working.html

------------

Temperature gauge went up?

http://schematicsdiagram.blogspot.com/2011/12/temperature-gauge-went-up.html

------------

Temperature gauge stays At cold on jaguar?

http://technoanswers.blogspot.in/2012/02/temperature-gauge-stays-at-cold-on.html

-----------

How to replace Instrument panel and dashboard on Toyota car?

http://repairhelpcenter.blogspot.in/2012/02/how-to-replace-instrument-panel-and.html

-----------

How to remove instrument panel on Chevrolet car?

http://technoanswers.blogspot.in/2012/02/how-to-remove-instrument-panel-on.html

-----------

How to remove control panel on Buick regal?

http://howtobyme.blogspot.in/2012/02/how-to-remove-control-panel-on-buick.html

---------------

These details will help.

Thanks.

Wiring problem under the dash. Could be a ground issue as you said. You need to get under the dash and check the grounds.

This is most likely 2 problems. The ABS/Brake light and speedo issue will be the speed sensor located in the read differential housing. The temp guage issue (and I'm assuming this is at idle) could be thermostat or temp sending unit. The fluctuation is causes by the electric cooling fan cycling on and off to control the temp. However, most of the time this fluctuation should be from about 195 - 220 degrees.

There's a float inside the tank that the fuel gauge works off of. If you step on the brakes or accelerate hard it causes the gas inside the tank to slosh around and you can see the fuel gauge move when you do this. If you know the vehicle has gas in it, the best way to check if the gauge is bad is to drive around enough to where you should have burnt a noticeable amount of gas. If the gauge doesn't move, then there's something wrong with it.


Since the gauge moved when you braked hard, I would assume it's working properly because it picked up on the level change inside the tank where the float's at.

Have the various systems scanned and see if they show a fault code, I suspect they will. As far as the gauges go that sounds like the rebuilder screwed up.

Oops. The brake light if on should be investigated first. The fluid level, is it low?

Also, if the check engine light is on, the codes should be read on an OBD-II scanner to get a clue as to what is wrong.

Check the gauge fuse for the gauges going out randomly. The gauge assembly may have a bad connection in the harness though.

the check gauges light is to tell you to look at the gauges,one of them is not in normal position,could be temp,oil pressure,charging,or gas.