water temperature gauge

[wilbertsvo]

I am the proud owner of an Esprit SE '90. Once the radiator fans are switched on, the temperature gauge jumps 10-15 degrees higher. When the fans are switched off the gauge jumps back 10 degrees. What can be the reason for this 'jumping gauge'? Is it a wiring problem? What should I check/change???

P.s. Also other gauges and interior light do react when turning on/off the radiator fans.

[Mike.Griese]

There is a voltage regulator in the instrument cluster that sounds like it could be your problem. Does your gas gage do funny things at the same time?

Mike
'83 Esprit Turbo (The Fabulous Trashwagon)
'05 Elise

[lotusguy]

Hi,

There is no Voltage Stabilizer in the GM ECU controlled cars - >'88.

Your issue sounds more like a poor ground or corroded connector in the binnacle harness. Check the wiring diagram and trace the appropriate wires, especially the ground and look for loose and/or corroded terminal or contact.
Happy Motoring!... Jim'85TE

[flowers]

Hi,

I had a similiar problem with my 79 S2, it turned out that the fans were turning the wrong direction. You can check by putting your hand in front of the front wheels (careful not to touch fan blades). You should feel air moving toward rear of car when they are on.

Rich Flowers
'79 JPS #040
'95 S4s ...SHF63000

[Mike.Griese]

lotusguy said:

Hi, There is no Voltage Stabilizer in the GM ECU controlled cars - >'88.

I never could remember that cutoff date...

Mike
'83 Esprit Turbo (The Fabulous Trashwagon)
'05 Elise

[wilbertsvo]

I have cut the ground (mass) wire from the gauge and directly put a new wire to the mass wire of my radio, but still I have the same problem when switching on/off the radiator fans. So it must be some voltage drop in the power supply (12V) wire of the gauge...

[wilbertsvo]

I checked my fans, working the right direction: they suck air through the radiator into car...

[wilbertsvo]

Did some more tests this evening. I sprayed all connectors with contact spray. No success....
After all I found out that when you turn on the radiator fans, also the radio has some voltage downturn of about 1 Volt, while it is on a different circuit than the binnacle... Can it be a ground problem of the radiator fans circuit???

[lotusguy]

wilbertsvo said:

Did some more tests this evening. I sprayed all connectors with contact spray. No success.... After all I found out that when you turn on the radiator fans, also the radio has some voltage downturn of about 1 Volt, while it is on a different circuit than the binnacle... Can it be a ground problem of the radiator fans circuit???

Hi,

Very definitely it could be a ground fault in the fan circuit. But it coiuld also be a myriad of other things as well.

You should really try to get a Freescan of the system (since the ECU controls so much) to see what it says is going on, if anything. It could straighten the path to a solution significantly.
Happy Motoring! ...Jim'85TE