Think Technician ESSENTIALS

First, the things you never do:

Never cycle the key while the heater is on.  Always turn the blower off before starting up or shutting down the car.  If you want the full story go to this page.  And there’s even a little bit more to the story on the Open circuit splices post.

Never disconnect the high voltage heater cable from the PCU unless either (a) the 12V battery is disconnected or (b) the low voltage heater connector is already disconnected.  (The low voltage heater connector is the one under the hood in the same vicinity as the high voltage connector.  It’s 3 wires and looks very similar to the connector to the brake booster vacuum pump.) If you have any doubt always just disconnect the 12V battery first.  Always make the low voltage heater connector the first thing you disconnect and the last thing that you reconnect.  It’s counter-intuitive to me, and that’s how I have killed many, many CDCMs and VCUs.  I don’t know why, but that’s just what happens.

When lifting a Think be mindful that the brake lines run just on the inside of the frame rails where you are likely to lift.

If you’ll be removing the traction battery for repair, make sure that the lift arms and pads will not interfere with the battery dropping out.  (I’m not going to publish my procedure for MLEC repair on this site, but if you are a service technician you can contact me for that information.)

Use Think TechCentre, aka Think Diagnostics, with the VIM/VCI/Black box with Think on it to check fault codes.  It’s easiest to read BMS fault codes in TechCentre, but to clear BMS codes you have to switch to the PCAN adapter and use CommTool.  There are other posts in this category that deal specifically with hardware and software.

Don’t leave Thinks for more than a couple weeks without charging the 12V battery.  You can charge the 12V battery by simply turning the car on so it’s ready to drive (little green car icon on the center console will be illuminated).  Just like conventional cars, if you let it sit for too long the 12V battery will become too discharged to start the car.  Depending on how discharged the battery is you may be able to jump start it through the accessory power port (above the fuse panel where you might expect a glove box), and/or you may need to have the 12V battery replaced.  More on this below…

Don’t leave a Think plugged in to an EVSE for more than a few days because once the traction battery charging is complete there will be an increased draw on the 12V battery.  I’ll elaborate:  While the traction battery is charging, the DC/DC converter is operational and this charges the 12V battery.  When the traction battery is done charging, the contactors open, and the charger (internal to the PCU) turns off, and there is no high voltage available to the car.  There is no 12V charger that works directly off of the EVSE supplied power.  The DC/DC converter only converters DC high voltage to DC low voltage.  But with the EVSE still connected to the car, computers inside the PCU stay awake rather than in their normal shutdown energy-saving sleep mode.  And that takes power.  And that will drain your 12V battery much faster than if you weren’t connected to an EVSE.

Jump starting a Think can be difficult depending on how discharged the 12V battery is.  You can apply 12V through the accessory power port to the left of the fuse panel in front of the passenger seat (where you might expect a glove box).  But sometimes there’s too much of a voltage drop through the fuse or you blow the fuse.  (You can also try applying power through the DLC, but the fuse to the accessory power port is 15A and the fuse to the DLC is only 5A– maybe try both!)  In that case you need to apply power directly to the battery:  Pop the hood and remove the cabin air filter duct which is secured by a Torx 25 screw; there’s not a whole lot of room, I use a tool called a Naro Driver. (Maybe you can weasel a jump box clamp down there without removing the cabin air duct, but if you have the tools it definitely makes it easier.) With the duct removed you can reach from the right side of the car down to the positive post of the 12V battery.  The plastic cover on the positive terminal comes off by pressing 3 tabs (there’s a photo in the 12V battery replacement post). The A/C compressor is a good ground.