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Water Temp Oil Pres Gauges erratic

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  • Water Temp Oil Pres Gauges erratic

    The OEM combination guage started acting up (as if a bad connection) . . Some times registering both values (water & oil) Then (as if) loosing power and not registering at all. Haynes indicates symptom is indicative of Accessory Relay (And other) problems. Not knowing what that Relay looks like, and where it is situated I figured I should assess the “other” first.

    Checked sending units (OK) for resistance. Grounded leads to sensors and the gauges register MAX which I understand indicates the gauges OK. Visual inspection of wiring OK (iI have much of the counsel/ dash out.

    Can anyone tell me if the Accessory Relay what I have Pictured? If that is it I can see it may well be the culprit as quite corroded. The next question becomes where to find a replacement?

    appreciate your all being here!

  • #2
    Sorry, typo second sentence it is the combo Water Temp/ Oil Pres gauge. All other gauges are working regular.
    I should have noted The Picture (relay) as shown mounted Is situated on drivers side engine bay inside fender near the coil.


    • #3
      Arnie, Is there still a visible number on the cover?
      How many pins in the connector 5 or 6?
      what are the wire colours?
      Last edited by Ont240; 08-22-2020, 09:58 PM.


      • #4
        The number on case is 25230-89905 IDECO
        6 Pins
        Red/Black(stripe) there are 2 leads this colour - Black/Red (stripe) - Red/White (stripe) again 2 leads this colour - Green/ Blue (stripe)


        • #5
          I don't recall of there ever being a relay in that location. Something moved? Is it wired to horns by chance?
          i have a used one that was covered with under coating.
          Have you checked the ground screw on the back of the gauge. Accessory relay is usually on passenger kick panel.


          • #6
            Found what that number is!!


            • #7
              DCADDF38-3B45-4241-811D-9B9300101137.jpeg18F11FE1-9832-47D8-8E68-3BBEB9D6AA1E.jpeg68B4E0FA-8519-4DCD-A0B0-8BDFD44DA732.jpeg From what i see there are 3 heater/resistor coils that are connected . I would suggest you try another gauge. Are your connections at the temperature sensor and oil sender tight fit?
              Last edited by Ont240; 08-23-2020, 11:36 AM.


              • #8
                Thanks for finding that number Laverne, obviously not the accessory relay but in need of improvement. If you are willing to part with that please hold for me.

                I Looked to passenger kick panel, and removed the Relay there it has numbers 26230-E4100 printed on case. Unfortunately the case dos not come apart so I cannot inspect the inner (like the previous).

                Checked ground (black lead) on gauge and it is secure. The black lead also checks full continuity to ground. The connections at sensors had been checked, cleaned, and seem very secure, and fit is tight on both (oil sensor is so tight I did not want to mess for fear of busting thread) one busted bolt on recent water pump replacement is quite enough for this round haha.

                I had suspected the gauge might be the culprit, but don't have a spare. Do you have one you could sell me? I would gladly take the drive to pick up, and make this issue another experience past. If so I will ring you, and we can make a plan.


                • #9
                  I have a couple of these gauges but don’t know how to check to see if it’s working. I might have that relay as well. Give me a call and we’ll sort it out.


                  • #10
                    I have the gauge as well.


                    • #11
                      The diagnosis you had Laverne was correct . . . You Nailed It . . . Thanks for all! I now have a functioning gauge.

                      Contrary other discussions I had looked to, and some Youtube postings the process of simply grounding out the lead to the sensor evidently does not totally indicate the gauge Is All OK. For those who may look to this post in future with similar trouble be aware.

                      As tested we found resistance to ground (black) to be 102 OHM (yellow) / 57 OHM (yelow-red) / 104 OHM (yellow-black) On my troubled unit. . . The same respective leads on the replacement gauge showed 518 OHM / 93 OHM / 124 OHM.

                      Although the wiring diagram, and information in Haynes points to an accessory relay (as possible source of problem) that could not be found. At least on my 9 of 71 production it was not found. The relay on passenger kick panel (I had the number wrong) turns out to be for heater/defrost.