temperature gauge pinned hot
when starting the car the temp. gauge jumps to red hot ....I've been driving the car for 15 minutes max. one way thinking that the car may overheat but so far the car seems normal at these short distances.
Since you are experiencing no overheating problems the most likely cause is that the engine coolant temperature sending unit is faulty. This sends a signal directly to the dashboard gauge. There is another coolant temperature sensor close by which sends a signal to the ECU to help in engine management. You shouldn't get confused between the two as the one you want only has one wire and the other has two.
Here is an image showing the two sensors. The one on the left, where the single wire black connector has been disconnected is the sensor sending unit to the dashboard gauge, the one on the right with the grey connector (and being held by fingers) is the ECU sensor.
Not quite certain if my figures are correct , but to test the sending unit, disconnect the single wire black connector and using a DMM (Digital Multimeter - Ohmmeter function) measure the resistance between the sending unit terminal and earth (or ground - the engine block will be earthed). With a cold engine the resistance should be approx 140 Ohms. With a hot engine it should measure 30-50 Ohms. If you measure around this value (or definitely not near 140 Ohms) with a cold engine then the unit is faulty and needs to be replaced.
A quick test is to disconnect the lead from the sending unit, turn on the ignition and observe the temp. gauge. If it registers 'zero' then most probably the sending unit is faulty. If however it still registers a 'full scale' reading then either you have removed the wrong lead, there is a fault in the wiring or there is a fault in the instrument cluster/temp gauge
Note: Be safety aware - always switch OFF the engine when you are going to work on it
Hi @Titus Bohanan,
Here’s a link to a service manual in which it details how to test the cooling system components, e.g. temp sender unit, fans etc.
I realize that it is not for your exact year model (it is for a 1998 -2002, couldn’t find it for your year model) but hopefully it will still be of some use.
See p.10-19 for the troubleshooting section regarding your problem with the radiator fans
According to the manual there is a radiator fan switch A and a radiator fan switch B and it suggests to check the circuit for radiator fan switch A when the symptoms are what you have, i.e. both fans (radiator and condenser) do not run for engine cooling, but they do run with the A/C on.
See p.10-7 for the coolant temp sender testing procedure to check if the sender unit is OK.
You will need a DMM (digital multimeter) as there is need for a Voltmeter and an Ohmmeter to perform the tests. Adequate DMMs are available from larger hardware stores for about $15-20. If you don’t know how to use a DMM get one that comes with a good user guide (some are woeful) so that it will be easier for you to understand and use. If you already know how to use a DMM, apologies.
To make reading the service manual easier, download the file to your computer. The download link is at the bottom of the Document page just to the right of where it says Zoom 100%
I have similar problem:
upon cold start gauge on dash goes to full red in 1 or 2 seconds.
When disconnecting single wire coolant sensor, and starting car gauge on dash stays at zero.
However, when replacing with new sensor, gauge on dash goes to full red at startup, very surprised by this.
(not possible the car is red hot yet at cold start)
This is the new sensor:
Wondering what else can check for, seems this coolant temp sensor is at the end of the line of things. There is nothing else feeding into that dash gauge right?
Wrong there are a total of three sensors that can effect your guage cluster 1 on the thermostat housing two on the end of the head and 1 underneath the head on the back of the engine all the sensors are in direct contact with the ECM so if it pegs at cold then first I would check the one on the thermostat housing first it may be giving a bad ground to the sending
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