When the front right headlamp heats up it begins to "short" out. Why? Local Nissan dealer says they have never seen this type problem before!

Suggest you try a salvage yard if no local dealer.

Dear Will,
Very highly likely you have the mechanism that does these tasks for you has quit working.
Whether you can fix it yourself, either way, you will need the mechanism to do the repair.
That will probably be available only at a Volvo dealer, or at the repair garage that does Volvo repair.
Call your local Volvo dealer and begin the quest to find how to go about the correction.
God bless your efforts.

No and if the loss of coolant is sudden, the temp gauge may not respond in time , Damage to the head and piston rings can happen in a very short time.

Well Jeni there are a few thing's that could be wrong , the headlamp switch , the BCM -body control module -a electronic control module . There are relays involved also ,but don't think there at fault . To be sure you need to do some electrical test to know for sure ! I suggest you take it to a ASE certified repair shop that has the knowledge , tools an service info - wiring diagrams etc.. ! Oh and a scan tool that can extract DTC'S from the BCM there could be a diagnostic trouble code pointing to the problem !
DTC B257A 00: Headlamp Switch Input Signal Mismatch
Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance
Headlamp Switch Off Signal
B257A 00
3
--
--
Park Lamp Switch On Signal
5
4
--
--
Headlamp Switch On Signal
B257A 00
2
--
--
Headlamp Ground
--
2, 3, 4
2
--

1. Headlamps Always On

2. Headlamps Inoperative From Switch

3. Unable To Turn OFF Automatic Headlamps

4. Park Lamps Inoperative From Switch

5. Park Lamps Always On
When the headlamp switch is in the OFF position, the body control module (BCM) receives a ground signal through the headlamp switch OFF circuit and an open signal on the park lamp ON circuit and headlamps ON circuit. When the headlamp switch is in the PARK or HEAD position, the BCM receives an open signal through the headlamp switch OFF circuit and a ground signal through the park lamp ON circuit or headlamp ON circuit.
Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the headlamp switch.
2. Verify that a test lamp illuminates between the ground circuit terminal 8 and B+.
?‡'
If the test lamp does not illuminate, test the ground circuit for an open/high resistance.

3. Ignition ON, verify the scan tool Auto Hdlp. Disable Sw. parameter is Inactive.
?‡'
If not the specified value, test the signal circuit terminal 3 for a short to ground. If the circuit tests normal, replace the BCM.

4. Verify the scan tool Headlamp Switch parameter is Inactive.
?‡'
If not the specified value, test the signal circuit terminal 1 for a short to ground. If the circuit tests normal, replace the BCM.

5. Verify the scan tool Parklamp Switch parameter is Inactive.
?‡'
If not the specified value, test the signal circuit terminal 2 for a short to ground. If the circuit tests normal, replace the BCM.

6. If all circuits test normal, test or replace the headlamp switch.

If the BCM needs to be replaced , it has to be programmed . The dealer is pretty much the only place to have that done at ! There are other places ,you have to look in the phone book or inquire at local repair shops . Some towns ,city's have mobile repair guy's that do flash programming of modules etc... Good luck hope I gave you some insight on the problem ! I tell people these thing's an it's like they don't believe me , I see they repost the same question . I started working as a Technician in 1984 at a Chevy dealer ship an have worked at Cadillac , Pontiac , GMC dealer ships ! I see all to often people trying to fix these type of problems by just replacing parts not knowing what they are doing an wasting there money an later bring it to the shop anyway ! So I hope you make a good decision an take to a qualified repair person or shop !

Cheaper alternatives are out there, but when it comes to remotes, it all depends on what you want it to do. To simply unlock the doors (if the car has electric locks) is cheapest. To unlock doors and a liftback, the price goes up. To unlock doors, liftback, and a fuel door, the price goes up again. Want a panic button? Pay again. (See where I am going with this?)

All kidding aside, there are cheaper alternatives. Look up your local window tinting places and/or car stereo installation places. They will be much cheaper than the dealer, but to be honest, I have seen the workmanship and quality that many of those types of places produce and you would have rather spent the extra $100 you would likely saved to get a well installed and serviceable solution for your Nissan. The car is already fitted perfectly for the Nissan parts. The aftermarket installers have to "jury rig" many aftermarket parts to get them to fit. Up to you. Good luck.

Hello your Dealer is going right by the book on labour now a day's garages are by law aloud to go by the book quote to do the job the book is about 7-8 hours but i have seen the job completed in 6.5 hours by someone who has allot of experience and has done several of them.So all in all they are aloud to go by the book and yes your quote is pretty much accurate and yes it is a big job hoist needed.

A couple of possibilities. You should consider changing thermostat and coolant. Also fan belt that drives waterpump should be replaced, and lastly new radiator/coolant cap (they do loose ability to hold pressure)

If you haven't already done so change the bulb and see if this corrects it. I broken element in the bulb will do this when the element bounces up and down and makes brief contact. If you have tried this then it could be caused from a broken wire on the headlamp harness or a bad headlamp socket. I would first remove the headlamp leaving it attached in the socket, with the lights on shake the harness and see if you can get the bulb to flash. If it does flash inspect the wires going to the headlamp socket for and damage or breaks and inspect the socket itself for a loose fitting bulb. If you find bad wiring repair it using water tight **** connectors that will need to be heated to seal the wires. If you find a bad or worn socket from excessive heat then contact you dealer or local junk yard for a replacement and again use water tight **** connectors or shrink tube.

I recommend 60-90K Cost depends on the dealerships labor but usually when your doing a timing belt, radiator hoses and fan belts are removed and should be replaced while your in there. Its about 3hrs, more if other things need to be replaced while in there. So you looking at $300+ for labor only

the only problem that vehicle has is with cooling fans is relay/module or electrical harness to module that burns up located behind and under right front headlamp assy must remove headlamp to access relay/module that is what powers up fan motor module assy.