On 2008 gmc arcadia my front wipers quit working at all. Any suggestions? Where is fuse for front wipers?

it is inside of the transmission. On this model it requires complete tear down of the trans to replace

RR/HVAC fuse 30amp located in the under hood fuse box. You can check it but highly doubt it's the problem . More then like it's the blower motor control module that's bad .
Circuit/System Description
The auxiliary blower motor is a variable speed fan. The HVAC control module controls the fan speed by sending a pulse width modulated signal to the auxiliary blower motor control module. The auxiliary blower motor control module varies the duty cycle across the auxiliary blower motor in relation to the pulse width modulated signal. The auxiliary blower motor speed can be adjusted from 10 percent to 90 percent duty cycle (PWM), 90 percent is high speed fan.
Watch this video for testing purpose's only , this is a front blower motor control module . Same way your back one works . GM is GM Chevy , Buick ,GMC , Cadillac .

If your not familiar with automotive electronics an module control of components , I suggest you take it to the dealer . They have the tools to diagnose this type problem !
The Wiper/Washer System consists of the following components:
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Windshield wiper/washer switch

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Body control module (BCM)

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Wiper PCB relay

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Wiper high PCB relay

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Windshield wiper motor

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Windshield washer fluid pump

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Windshield washer fluid level switch

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WPR fuse 25 A

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WSW fuse 10 A

Low Speed Operation
When the wiper switch is in the low speed position, ground is applied through the switch internal resistor and the wiper switch low signal circuit to the body control module (BCM). In response to this signal, the BCM energizes the WIPER PCB relay by applying battery voltage through the wiper relay control circuit to the coil side of the relay. This allows battery positive voltage from the WPR fuse to flow through the switch input side of the WIPER PCB relay and out to the switch input side of the WIPER HIGH PCB relay. Since the wiper high relay is de-energized and its switch contacts are normally closed to the low speed control circuit of the windshield wiper motor, the motor will operate at low speed.
High Speed Operation When the wiper switch is in the high speed position, ground is applied through the windshield wiper switch high signal circuit to the body control module (BCM) indicating the wiper high speed request. In response to this signal, the BCM then energizes the wiper PCB relay, as stated above, and the wiper high PCB relay by applying ground through the control circuit to the coil side of the relay. With the wiper high relay energized and its switch contacts closed to the high speed control circuit of the wiper motor, the motor will operate at high speed.
Wiper motor high speed operation and the wiper high speed PCB relay can also be commanded ON/OFF by using a scan tool. Refer to Control Module References.
DTC B3715 02: Front Wiper Relay Drive Circuit Short to Ground
DTC B3875 00: Wiper High Speed Relay Circuit
DTC B3922 00: Front Wiper Function Select Circuit
You could Have a switch problem , BCM problem ,PCB relay problem , the pcb relays are non serviceable an the whole under hood fuse box would need to be replaced . Malfunctioning motor bad ground some where etc.....

In Underhood Fuse Block 25 AMP--Is B+

The acadia has two common problems for front end noises. You likely have worn lower control arm bushings. You will need both front lower control arm bushings. Also it is common for the struts to wear out from about 75k miles up. If they are leaking or have a harsh ride you should replace those as well.

Same as with all vehicle issues

Check the fuses

Then get out the Wiring Diagrams & get familiar with the
system & pick a test point, or start taking things apart, to get
to the motor or your test points,the most logical part to
have possibly failed

No one can do that for you or tell you what the problems are

Always need a vehicle to test

Get a new mechanic. Or a technician would be better. If it.s not the wiring then its probably the motor.

FIRST CHECK THE CONDITION OF YOUR RADIATOR, IT MY NEED SERVICING OR REPLACING,IF OK, CHANGE THE THERMOSTAT IT MAY BE STOCK IN THE CLOSE POSITION ALSO CHECK FOR LEAKS AND CHECK TEMP SENDING UNIT. IF ALL THAT CHECKS OUT OK YOU MA HAVE A BLOWN HEAD GASKET

There were some issues with ignition switches in those vehicles.It is easy to change and does not cost but about $30. Remove the column covers, unplug the switch, and depress the 2 white tabs holding it in place. Good Luck