Toyota's various PTC Quick Heaters

Ongoing discussion of anything not related to Nissans or diesels.

Moderators: goglio704, Nissan_Ranger, kassim503

Post Reply
User avatar
asavage
Site Admin
Posts: 5365
Joined: 15 years ago
Location: Duvall, Wash.
Contact:

Toyota's various PTC Quick Heaters

#1

Post by asavage »

I am looking for more driver's footwell heat. On old-school battery electric vehicles (BEVs), ones that don't utilize a heat pump -- as most modern BEVs do -- the electric heater is a significant energy consumer. My old 2014 Toyota RAV4 EV, which is based on the 3rd Generation RAV4 (2005-2012), does not use a heat pump for cabin heating. Instead, it has a Denso water heater that runs off the HV (~400vdc) traction battery pack; it heats water, then an electric pump moves the hot water to a typical heater core, just like an ICE vehicle. The Toyota Rav4 EV of 2012-2014 was a rush job, the result of a collaboration with Tesla, who supplied the EV drivetrain and battery. It was designed to meet California ZEV compliance regs and didn't have a lot of engineering :(

My winter range is around 20-25% less than my summer range, mainly due to the high electrical energy consumption of this cabin heating arrangement.

My normal 60 mi./day commute is no problem, even when running the heater "full blast". But with the OEM heated seats, and appropriate clothing, I could run the cabin heat a lot lower than I have been -- other than getting cold feet. On certain trips, I sometimes want a bit more range cushion, so I've been looking at spot heating just my footwell.

Positive Temperature Coefficient (PTC) heaters are everywhere, and cheap. They have the unique property of getting just so hot, and no hotter. Initially, I was looking at the usual offerings on eBay, Amazon, etc.
Heater_Generic_Ceramic_12v_01b.jpg
Heater_Generic_Ceramic_12v_01b.jpg (48.52 KiB) Viewed 714 times
Heater_Generic_Ceramic_12v_02b.jpg
Heater_Generic_Ceramic_12v_02b.jpg (68.09 KiB) Viewed 714 times
Heater_Generic_Ceramic_12v_03b.jpg
Heater_Generic_Ceramic_12v_03b.jpg (41.59 KiB) Viewed 714 times
Heater_Generic_Ceramic_12v_04b.jpg
Heater_Generic_Ceramic_12v_04b.jpg (61.1 KiB) Viewed 714 times
I even ordered a couple. But, they are all so cheaply constructed that I began looking for something more robust. Toyota has been installing small PTC heaters in many of their vehicles since at least 2009; they're set up to provide a bit of heat when the ICE's coolant temp is low, particularly in cold climates or in versions of vehicles with diesel engines, which generate little heat when not loaded.

As it happens, my RAV4 EV already has a PTC heater installed. It's 840W capacity, three stage, and I guess it provides a bit of warmer air until the main water heater gets up to temp. I never noticed if it does much.

[Side note: to access/replace the PTC Heater in my vehicle, there is an enormous amount of work involved. The A/C Assy. has to be removed, partly because the PTC's integrated wire harness is sandwiched between it and the firewall. In order to remove the A/C Assy., you have to remove: front seats, carpet (partial), outside cowl, wiper motor, drain coolant, console, pretty much the entire dashboard, the horizontal dash mount tube, etc. It sounds awful to accomplish. Same labor to replace the water heater core.]

eBay has loads of used Toyota PTC heaters for cheap. I'm thinking of hanging one above my feet with a fan and some switchgear, for use when I'm trying to make a bit extra range in cold weather. Note that modern BEVs generally don't have to sweat range like my old rig; they're both more energy efficient (my old RAV4 EV is a bit more aerodynamic than a brick), have more efficient drivetrains, and have heat pumps that provide heat at moderate temps at a much lower energy usage.

The three most common Toyota PTC heaters are 330W, 495W, and 840W -- the latter is NLA. Below I summarize my best guess as to the applications in which each was installed. Bear in mind that the PTC Quick Heaters were not optioned in all markets nor all versions of a model. Notably, their are PTC heaters installed in Gas-engined vehicles and Cold Climate Diesel-engined vehicles, with two-stage heaters/wiring/relays, but Diesels in non-Cold Spec. got the three-stage units. Go figure.

Below, I document some info and circuit diagrams I've pulled from various sources. Some is redundant, esp. the multiple circuit diagrams, which all show pretty much the same circuit but in differing detail.

Toyota 87710-02040
Denso 094800-0121
12v 330W

2011-2016 RAV4 (VIN starts with '2')
2017-2018 RAV4 (some Limited/SE/Platinum)
2009-2013 Matrix
2009-2019 Corolla (with cold spec.?)

Toyota 87710-12020
Denso 094800-0051
12v 495W

2009-2017 Corolla (some)
2009-2017 Prius
2013-2018 RAV4
2015 RAV4 (2WD Outdoor Limited, Premium Limited)
2016 Scion iM
2011-2017 Lexus CT200h

Toyota 87710-42040 (NLA)
Denso 094800-0140
12v 840W (three connectors)

2008-2012 RAV4
2012-2014 RAV4 EV
Toyota 330W PTC Quick Heater
Toyota 330W PTC Quick Heater
Toyota_PTC_330W_87710-02040_01b.jpg (982.98 KiB) Viewed 714 times
Toyota 495W PTC Quick Heater
Toyota 495W PTC Quick Heater
Toyota_PTC_495W_87710-12020_01b.png (1.74 MiB) Viewed 714 times
Toyota 840W PTC Quick Heater
Toyota 840W PTC Quick Heater
Toyota_PTC_840W_87710-42040_02b.jpg (264.38 KiB) Viewed 642 times
Toyota 840W PTC Quick Heater, connectors view
Toyota 840W PTC Quick Heater, connectors view
Toyota_PTC_840W_87710-42040_04b.jpg (270.66 KiB) Viewed 642 times


A couple more views of the later 495W unit:
Toyota 495W PTC Quick Heater
Toyota 495W PTC Quick Heater
Toyota_PTC_495W_87710-12020_02b.jpg (235.86 KiB) Viewed 710 times
Toyota 495W PTC Quick Heater: Denso part No.
Toyota 495W PTC Quick Heater: Denso part No.
Toyota_PTC_495W_87710-12020_04b.jpg (139.62 KiB) Viewed 710 times
Toyota 495W PTC Quick Heater: connectors view
Toyota 495W PTC Quick Heater: connectors view
Toyota_PTC_495W_87710-12020_05b.png (1.2 MiB) Viewed 710 times
Toyota 840W PTC Quick Heater: installation location in 2012 RAV4
Toyota 840W PTC Quick Heater: installation location in 2012 RAV4
Toyota_PTC_840W_87710-42040_01b.png (547.53 KiB) Viewed 709 times
Toyota 840W PTC Quick Heater: Denso part No.
Toyota 840W PTC Quick Heater: Denso part No.
Toyota_PTC_840W_87710-42040_03b.jpg (121.54 KiB) Viewed 709 times
Toyota 840W PTC Quick Heater: Connector terminals diagram (early w/(3) connectors)
Toyota 840W PTC Quick Heater: Connector terminals diagram (early w/(3) connectors)
Toyota_PTC_840W_87710-42040_07b.png (121.03 KiB) Viewed 703 times
Toyota 495W PTC Quick Heater: Connector terminals diagram (late w/(2) connectors)
Toyota 495W PTC Quick Heater: Connector terminals diagram (late w/(2) connectors)
Toyota_PTC_495W_87710-12020_06b.png (139.99 KiB) Viewed 707 times
Toyota 840W PTC Quick Heater: Early RAV4 relays location/information
Toyota 840W PTC Quick Heater: Early RAV4 relays location/information
Toyota_PTC_840W_87710-42040_08b.png (394.41 KiB) Viewed 708 times
Typical Toyota PTC circuit, including both 2- and 3-stage PTC installations
Typical Toyota PTC circuit, including both 2- and 3-stage PTC installations
2013-2014_Toyota_RAV4_Aux_Heat_Circuit_01b.png (195.43 KiB) Viewed 701 times
Typical Toyota PTC circuit, including both 2- and 3-stage PTC installations
Typical Toyota PTC circuit, including both 2- and 3-stage PTC installations
2013-2014_Toyota_RAV4_Aux_Heat_Circuit_02b.png (57.9 KiB) Viewed 701 times
Typical Toyota PTC circuit
Typical Toyota PTC circuit
2013-2014_Toyota_RAV4_Aux_Heat_Circuit_09b.png (168.87 KiB) Viewed 699 times
Typical Toyota PTC circuit
Typical Toyota PTC circuit
2013-2014_Toyota_RAV4_Aux_Heat_Circuit_09b.png (168.87 KiB) Viewed 698 times
Typical Toyota PTC circuit
Typical Toyota PTC circuit
2013-2014_Toyota_RAV4_Aux_Heat_Circuit_E269929E02_05b.png (39.73 KiB) Viewed 697 times
Typical Toyota PTC circuit
Typical Toyota PTC circuit
2013-2014_Toyota_RAV4_Aux_Heat_Circuit_E273611E01_06b.png (28.77 KiB) Viewed 697 times
PTC system description
PTC system description
2013-2014_Toyota_RAV4_Aux_Heat_Circuit_03b.png (335.35 KiB) Viewed 701 times
PTC system description
PTC system description
2013-2014_Toyota_RAV4_Aux_Heat_Circuit_04b.png (155.39 KiB) Viewed 701 times
PTC Relays testing info
PTC Relays testing info
2013-2014_Toyota_RAV4_Aux_Heat_Circuit_07b.png (63.62 KiB) Viewed 701 times
PTC Quick Heater location in A/C Assy.
PTC Quick Heater location in A/C Assy.
2013-2014_Toyota_RAV4_Aux_Heat_Circuit_08b.png (776.57 KiB) Viewed 701 times
PTC Quick Heater location in A/C Assy., left side view
PTC Quick Heater location in A/C Assy., left side view
2013-2014_Toyota_RAV4_Aux_Heat_Circuit_11b.png (164.08 KiB) Viewed 701 times
Regards,
Al S.

1982 Maxima diesel wagon, 2nd & 4th owner, 165k miles, rusty & burgundy/grey. Purchased 1996, SOLD 16Feb10
1983 Maxima diesel wagon, 199k miles, rusty, light yellow/light brown. SOLD 14Jul07
1981 720 SD22 (scrapped 04Sep07)
1983 Sentra CD17, 255k, bought 06Jul08, gave it away 22Jun10.
Post Reply

Who is online

Users browsing this forum: No registered users and 3 guests