Symptoms: Coolant temperature gauge is erratic or non-functional; possibly no heat from the climate control.
There are two possibilites. The first thing to check is the thermostat, because it's easier and cheaper. If that's not the problem, you may need to replace the multi-function temperature switch per instructions below.
- Follow upper radiator hose to housing attached to block. On lower part of this housing there is a multi-function sensor with a rubber boot with 4 or 5 wires sticking out , and a bronze or copper colored hexagonal shape. It is threaded to housing (normal thread direction).
- With engine cold or lukewarm: Run a small screwdriver carefully around the perimeter of the boot, between the boot and the sender body. The intent is to separate any stickiness. Push down the boot from the upper edge and work it down. (Do not pull down the wires).
- There is a plug in connector inside with 3 or 4 contacts. The boot going down will disconnect the plug.
- Prepare the replacement part next to you so that you don't have to walk away. Place absorbent towel or rag underneath the sender.
- Using an open end wrench loosen sender and finish extraction by hand but maintaining slight upward pressure to avoid excessive coolant loss.
- When sender completely loose, pull it out and plug opening with left hand index finger. Make sure you have the flat washer on the sensor you pulled. If it lodged into the hole, pry it out. The new one will leak with two on there.
- With right hand (quickly without panic) insert new sender and initiate thread. Do not over-tighten with wrench (brass threads).
- Reconnect plug redress boot and clean the coolant from the block etc. If you broke the tabs, don't worry, just about every replaced sensor has broken tabs.
- Warm up engine check for leaks and enjoy your new temp reading and ECU performance.
