Water/Oil Warning Lights Inop
August 18th, 2017, 06:42 AM
#1
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Join Date: Apr 2012
Location: Columbus, IN
Posts: 120
Water/Oil Warning Lights Inop
After the engine swap I've noticed my water and oil warning lights no longer work. The fuel gauge and alternator light work fine. I'm using the same good water temp sensor from the old engine, and a new oil pressure sensor. Neither light turns on when the wiring connection to the sensor is grounded.
I can't seem to find any relevant wiring diagrams. The closest I could find is a Chevelle wiring diagram, which I would imagine might be similar. If the Cutlass wiring is similar, it provides power through a common node to all the circuits in that gauge, then have individual wires that go to their respective sensors. Is that the case with the Cutlass? Any common failures I could check first? Otherwise it seems like it's a long, unpleasant case of tracing wires and checking continuity, likely on the ground side.
I can't seem to find any relevant wiring diagrams. The closest I could find is a Chevelle wiring diagram, which I would imagine might be similar. If the Cutlass wiring is similar, it provides power through a common node to all the circuits in that gauge, then have individual wires that go to their respective sensors. Is that the case with the Cutlass? Any common failures I could check first? Otherwise it seems like it's a long, unpleasant case of tracing wires and checking continuity, likely on the ground side.
August 19th, 2017, 08:10 AM
#3
Old(s) Fart
Join Date: Mar 2007
Location: Northern VA
Posts: 47,311
Have you looked in the Chassis Service Manual, Chapter 12?
These are about the simplest circuits on the car. The bulb gets switched 12V power on side. The other side goes to the sender, which connects to ground to complete the circuit. The oil sender grounds with no oil pressure, the temp sender grounds with excessive temp. If the bulbs don't light when you connect the sender wires to ground, you have disturbed these wires. Find the break in the wires.
These are about the simplest circuits on the car. The bulb gets switched 12V power on side. The other side goes to the sender, which connects to ground to complete the circuit. The oil sender grounds with no oil pressure, the temp sender grounds with excessive temp. If the bulbs don't light when you connect the sender wires to ground, you have disturbed these wires. Find the break in the wires.
September 4th, 2017, 10:48 AM
#4
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Join Date: Aug 2017
Posts: 21
Hey!
I think I don't need to open a new thread for this.
I got a 1959 olds dynamic 88 and I'm in the process to remove the after market gauges with original dashboard lights for Oil Pressure and water temp.
So I removed the sensors and put brandnew originals in for oil pressure (works fine) and water temp (cold works fine).
Hot should show up when turning the key to start the engine, to show its working but it don't. It's working properly, if I connect the wire from sensor to ground.
So my questions is, which cable from the ignition switch will be the one to check? I don't want to mess something up and I can't find a wiring diagram with cable colors and/or position at ignition switch.
Got the original service manual but no colors showing up there. Would be nice if someone could help out.
Markus
I think I don't need to open a new thread for this.
I got a 1959 olds dynamic 88 and I'm in the process to remove the after market gauges with original dashboard lights for Oil Pressure and water temp.
So I removed the sensors and put brandnew originals in for oil pressure (works fine) and water temp (cold works fine).
Hot should show up when turning the key to start the engine, to show its working but it don't. It's working properly, if I connect the wire from sensor to ground.
So my questions is, which cable from the ignition switch will be the one to check? I don't want to mess something up and I can't find a wiring diagram with cable colors and/or position at ignition switch.
Got the original service manual but no colors showing up there. Would be nice if someone could help out.
Markus
September 5th, 2017, 09:20 AM
#5
Registered User
Join Date: Aug 2017
Posts: 21
59 olds HOT bulb
One step forward...
Oil and HOT bulb hang on the same plus line at the instrument panel.
Oil Bulb goes immediatly off, when turing the key to start position and it's still grounded cause there is no oil pressure at this time.
HOT Bulb only comes up with ignition on and ground the red wire from sensor or the purple one from ignition switch. Both ground the bulb and plus is always there with ignition on.
My guess is, cause Oil and HOT both do not light when STARTING, there is no plus voltage to the instrument cluster at start position. There are additional gauges with light, they come up with ignition on and lights off with starting.
Which cable should be missing / broken here? All 6 are connected to the ignition switch.
Any ideas how to go on from here?
Oil and HOT bulb hang on the same plus line at the instrument panel.
Oil Bulb goes immediatly off, when turing the key to start position and it's still grounded cause there is no oil pressure at this time.
HOT Bulb only comes up with ignition on and ground the red wire from sensor or the purple one from ignition switch. Both ground the bulb and plus is always there with ignition on.
My guess is, cause Oil and HOT both do not light when STARTING, there is no plus voltage to the instrument cluster at start position. There are additional gauges with light, they come up with ignition on and lights off with starting.
Which cable should be missing / broken here? All 6 are connected to the ignition switch.
Any ideas how to go on from here?
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