Ok, hello everyone. I am resurrecting an '05 LR3 SE with 165K miles. Made some significant gains getting a Christmas tree lit dash board down to a single CEL for a transmission fault. This vehicle had severe water leakage (what LR3 doesn't, right), and I was able to address many problems from re-splicing the wires in the driver/passenger foot-wells. I am now trying to address the issue of the seat heaters not working, none of them. The indicator lights on the climate controls light up properly, but my buns are cold as my ex-wife's birthday hugs. I have read up on a series of forums, and read how many had to replace components within the seats, however I am suspecting there may be a broader solution, being none of the seats work....? Here is what I have done thus far:
Re-spliced wires, notably the Green/Black wire on the passenger side (very thick)
Changed out all the fuses F7/F8 in engine compartment
Several Hard Resets, some with climate control module unplugged
ECU resets through IID GAPTool
Visual inspection of undersides of all the seats, connectors in tact
Lastly, rain dance with necklace of rabbits feet around my head, for an immaculate repair
Things to note, the truck had sat for quite some time (4 to 6 months) with the wet interior condition. The power controls on the front seats work perfectly fine, along with seat belt sensors. I had to change out the amplifier, and there was visual evidence of corrosion/rusting/molding throughout the interior cabin areas. I have examined wiring diagrams and could not tell for certain if one corroded seat heater could disable the usage of all the remaining seat heaters? You never now with Lanny's....I've begun on the super inexpensive list of possibilities, and now thinking that the seat heater modules may need to be replaced, as a result of the extensive moisture and corrosion while it sat?? Any best ways to test or identify what could be causing none of the seat heaters to work.

 

Did you test for voltage at the plugs when turned on? Did you look into testing the actual seat elements? The elements themselves tend to fail from what I understand. The wires crack from stress of being sat on. This seems to impact the back unit as well. I myself have no heat on teh driver side. Passenger side works, but its pretty poor - which is normal I guess as these seat heaters dont perform well.

 

I didn't test the voltage at the plugs when turned on....by "turned on", I am assuming when the heat seater is engaged by the switch itself? I have read a number of threads regarding the elements, and that was my first go to, until I saw that all the seats (front/rear) were not responding. It could be that all the Seating Elements would need to be changed out (I would not be all surprised from the neglect that I had uncovered with the rehab of the vehicle).
Course of action
1. Will be to test the voltage of each unit, after switch has been engaged.
2. If needed, confirm the status of the Seat Elements, I will post pics, if I get to this option for more advisable support.

 

 

My drivers side heater broke after about a month of getting a hot spot that would burn my *** if I sat there long enough. The passenger and rear worked, just the one was not working. There are fuses, relays and fusable links under the hood by the battery to check. There are also fuses behind the glove box to check.

The broken resistor wire is a simple fix, most difficult part was getting the leather seat cover off.

• The harness is under the seat
• The seat is held on by 4 torx screws, very easy to remove and there's no need to pull the whole seat.
• Unplug and confirm voltage at the harness (red wire I believe)
• If no voltage, pull the leather seat cover off. This was the most difficult part of the job.
• Left and right lower seat covers are identical, so I switched them to hide that tear caused by getting in and out of the truck!
• The broken resistor wire should be easy to find, just look for burnt foam.
• Cut the resistor wire back to clean wire, tinn both sides for a clean solder with rosin-core solder, and solder in a new scrap of wire. I used a two inch scrap of 18 awg. Let the solder cool without moving for a strong solder connection.
• Recover and reinstall. Mine's been going strong for over a year.

 

The heater buttons activate relays under the hood. Those relays deliver higher amperage (I believe 40 amps) to the actual heater elements. I'd start with the relays if you're not getting heat on any seats. There are several identical relays, so just switch one out and try the heaters again. If they work the swapped relay is bad. My seat heaters take about 2 minutes warm up. Good luck!