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Temperature gauge gremblin


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The digidash temp gauge on my 86 GL-10 SW EA82T 4x4 is possessed. It only works in a narrow temp band. Is the sensor for it near the thermostat (1 contact) or is it combined in the ECU (2 contact) sensor in the back near the knock sensor.

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  • 2 weeks later...

If I remember correctly the indicator does only show a single or sometimes a couple of bars as it follows the temperature changes. I suspect the trouble you are having is due to a problem with the indicator rather than the sensor. The digi dashes had some problems due to poor solder connections among other things. I think you have a bad connection to the indicator in the dash causing this trouble.

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If it's the same as my 88-1.8 T, the sensor is burried under the turbo on top of the crank case. I've had the same problem with mine. Replaced the sender, but no help. I think next I'll try G.D.s idea with the poor ground. Keep us posted. Thanks S.

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I have the 86 FSM but its somewhat unclear about which temp sensor feeds the digidash. It shows the single terminal sensor by the thermostat as the "needle" style gauge sensor (as opposed to digidash) and the two terminal sensor (by the knock sensor) as the input to the ECM as well as an input to temp gauge (two separate circuits in same sensor assembly). :confused:

However I like simple so I'll ground out the single terminal sensor lead and see what happens. I'll be taking the dash apart to check for other electrical issues as soon as I get some good schematics.

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  • 2 weeks later...

UPDATE: OK took out the digidash & reseated all connectors and tightened up every thing I could. Gauge is staying on longer now, single traveling bar along the scale. The single terminal sensor by the thermostat is for the gauge and the two terminal sensor by the knock sensor is for the ECM. As soon as I get some help I'll try jiggling the sensor terminal to see if its has a short.

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  • 6 years later...

i had a couple of possible reasons as to why this is happening and hopefully it will lead to a fix of some kind. or at least a way to know what the temp is while just ignoring the dash alltogether. one is the voltage regulator in the digi dash itself is going bad. i dont know if it has one or not but it would seem likely as a means of protection for the digital components. i pulled mine out as best as i could without disconnecting anything ( is 12 am and i gotta workat 9 but was curious) and there is a rectangle box. not sure if its the blinker indicator or a regulator. but seems a replacable enough part. i see two black wires that leave the plug on the drivers side. if looking at it like youre driving and you tilt the cluster top towards you. there is aa black with white and a straight black i can only assume is the ground. i didnt bust out my meter. but i will/ as well as try to ground it if it is when i do test it. and report back. and then theres teh regulator on the alternator. it could be good enough to charge the battery and keep the electricals running. but it may have a modulation or noize effect that causes it to act like alternating current and make things that are sensitive to electrical variables to just give a bad reading or cause multiple or all bars light up. replacing the alternator doesnt always fix this problem but what about a bridge rectifier after the alternator and then into the system to prevent there from being a modulated or pulsed current? if the alternator could cause one. . 

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Very old thread. A bridge rectifier "after the alternator " would do nothing to improve the stability of power . It would cause other problems, specifically, undercharging of the battery, due to the voltage drop in the diodes. There is also the problem of wiring one correctly, since the f rqme of the alternator is grounded, and a bridge rectifier is not going to function as a bridge rectifier with any 2 of its terminals tied together.

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