Why does my ac unit on a grand marquis mercury kick on and off?

There isn't one. The 1995 Grand Marquis uses a lighting control prossessor. They are very expensive to replace. The part cost me $325.00.

I have a 1996 Grand Marquis. If one of the brake lights goes out the signal on that side flashes faster. I would check the brake/tail lamps.

Look inside the trunk for the wing nuts to remove the unit.

Take it to the mechanic.

Where is it located on the engine

You don't. It is a sealed unit.

connect a diagnostic scanner and see what fuel percentage is showing.

on mine i had a premium sound system package stock. i had to bypass the stock amp to run the head unit even though i am running it on the pre amp from the head unit. the speaker will notwork unless you bypass the the stock amp.

Fill the tank Does the gas guage read correctly? If not replace the fuel sending unit after you drive enough to empty the tank to less than 1/4 full

In the center of the dash. It's the unit you select options on. It controls the AC and Heat.

You should have 2 silver cylinders in your fuse panel. About the size of a half dollar. Those are your flashers. You can feel if they are working. Put your turn signal on, and touch them. you will feel something moving inside them if they are working.

I have a 95 and the unit is located on the oil filter housing assembly. It is just a little ways up from the oil pressure relief valve, which is facing towards the ground. The sending unit has a wire/tube attatched. The attached end sholud be facing toward the front end of the car if I remember correctly.

Check for wing nuts in the trunk. Should be 3, then just pull out the unit from the out side.

Any mercury dealer can provide this information. NO RECALL,DEALER WONT TELL YOU ANYTHING,IS A DEFECT ON AIR INTAKKE GASKET UNDER WINSHIELD WIPER UNIT,PASSENGER SIDE,WARRENTY RUNS OUT GASKET SHRINKS AND WATER POURS IN EVERY TIME IT RAINS OR SNOWS,IF YOU CAN GET TO IT, JUST SILICONE AROUND IT.

Yes, it can. But on a 1994, you are better off discharging the system, replacing the unit as a whole, and then recharging the system. This will enable you to find any problems in the A/C system that are unknown.

I suspect that your Control Unit itself has gone bad. That's what happened to me. A new control unit will cost between $400 and $500. I got one from a Junk Dealer for $100. It's been working for 3 years now. The control is real easy to change out. Hope this helps.

If you have Climate Control, the Climate Control Unit has gone bad. This is the unit inside of the car that you use to select A/C or heat. It would have a digital readout. You can usually get one from a junk yard for about $100. A new one is over $400. It's very easy to change out.

If this is the case, try disconnecting the ac compressor. If not that, it could be in the 'master switch' (turn signal lever unit). Does anything else go out along with the turn signals? Does it only happen when you turn on the heater or ac?

IT is probably the oil temperature sending unit. Costs less than $10.00 to replace yourself.

there is a awitch on the chassis rail that needs to be bled, or replaced either go to a mechanic or get a workshop manuel this switch is called hydraulic control unit (HCU)

If you have the climate control heat/AC with the Auto setting your fan is a variable speed unit that has solid state controller. Very common for this controller to go out. The unit is mounted under the hood about 12 inches to the right of the fan motor. directly back from the right side valve cover. The unit ia about 4X2" with a connector on the right side. This unit can only be purchase at your dealer. difficult to change but it fixed my problem.

The turn signal/hazard flasher is accessed from below the left end of the dashboard with the kick panel removed.

Locate the sending unit, usually driver's side front of engine, unhook wire, unscrew unit using deep well socket, screw in new unit, re-hook wire, off you go. Just don't try it with a HOT engine.

The Goodyear shop at Boynton Beach Blvd and Jog Rd in Boynton beach quoted my son $380 to replace the Oil Filter Adapter gasket and Oild Sending unit. To me, that is more than just a little on the high side.

The air mix door on the in cab part of the unit is stuck in the heat position. follow the cables down from the controls on the dash and you will find the lever that controls the mix door, flip it the other way. for repair you will need to disassemble the heater unit if the cable has not just come loose from the arm.