Help! Oil/coolant light flashes after the machine runs for 5 seconds or so. We tried grounding out the coolant sensor...same thing happens. Removed the oil sender wire and the same thing. I unplugged the coolant sensor relay...same thing. If we plug in the bypass wires on the back, the machine will run but the oil/coolant light blinks. Any help would be greatly appreciated. Thanks, Robert
Check the Level sender relay. You should be able to just unplug the level sender relay, and unplug the engine oil pressure switch and it should run. If it doesn't run with both of those unplugged, the display may be failed as in the last post. The GB wire should not have ground with the relay and oil pressure switch unplugged. Check this at the oil pressure sender.
Gary, if I unplug the relay marked Safety Bar Switch,Coolant Level Relay,Emergency Relay, and the oil pressure sender, the machine will not run. Turns over but won't crank. With the relay plugged back in and the switch on, the GB oil sender wire has ground and the engine will run for 5 seconds and shut down. The relay I unplugged is marked K on the Electrical System diagram.
Also Gary, the GB wire does not have ground until you turn on the key. Also, what post were you referring to about the display? Thank you for your help, Robert Crews
We also have low voltage feeding the K relay. A test light is very dim and a auto ranging volt meter picked up 0.
Look for this thread : "Tl130 won't start has coolant and low old psi light on" It ended with him saying the gauge assembly failed. See schematics attached. Should be the same as your mustang. K should be the correct relay. 1. So with the k relay unplugged, and oil pressure sender unplugged, was there ground at gb wire? 2. With k relay unplugged you said "Turns over but won't crank." ??????? Did you mean turns over but wont start? All that happens in this circuit is the GB wire gets grounded when there is no engine oil pressure, or low coolant level.
Yes, it won't start with K unplugged and GB disconnected from the sender. What about the low voltage to K? We have since found a bad shutdown solenoid and I ordered a new one. It will be in by Wed but that is not the problem for sure. I don't think it would cause the lights to indicate there is a oil pressure or coolant problem and then shutdown. I checked GB for ground with K plugged in. I'll unplug it and check it Tuesday. Darn thing is about to drive me crazy. I dreamed about it!
If GB has ground with oil pressure switch unplugged, and the k relay unplugged, the wire is probably shorted to ground, or the gauge assembly failed.
Ok, there is no ground to GB with K totally unplugged. Engine turns over but does not start. With all plugged back in, we have checked the oil pressure sender, coolant level shorted for bypass, and it still shuts down after 5 seconds with the oil/coolant light blinking. It's still driving us crazy!
K. Sounds like the wiring is good. I don't thing it needs to, but maybe the cluster needs to see that the relay is plugged in? Leave K relay plugged in, and unplug oil pressure switch. Check GB for ground, with key on. If there is ground, you have bad relay/coolant level sender/detector. Have you swapped relays?
Gary. GB does have ground wit k plugged in.
okay. So that tells us that the relay is not clicking over. Refer to schematic. Bad relay, bad detector, bad diode, or low power to the relay. Pin 1 should have 12v with key on. Pin 2 should have ground, with coolant level sender in bypass. A quick test would be to break the tabs off of pin 30, and 87, on a relay, and pugging it back in. That would leave the ground open, and should let the module think the relay is there.
Ok thx. We'll give it a shot tomorrow. We sure appreciate your time and help.
We switched the relays still the same. Not sure how to sub a reg relay for it cause the wiring on the schematic doesn't jive with the machine. I'm lost. It looks to me there's three relays built into one so? Anyway, shouldn't it run with out it plugged in? It will turn over but not start.
I cut the GB wire going into the gauge cluster and the unit runs fine so it's not the gauge cluster. I really don't want to but may just hook gauge cluster to oil pressure sender and forget the level relay. Switched the two relays and it started and ran 5 seconds or so and shut down. What about the detector? Thanks for any help !
The detector is what switches the relay on, and removes ground from wire GB. Unplugging the relay should have removed the ground from GB, and allowed it to run. All I can think of, is either you unplugged the wrong relay, or you have different wiring than the information I have.
I pulled GB out of the plug on K and it runs fine. Everything else on K was plugged in and the oil sender was still in the circuit. I tested it. Got to be that relay or the detector or both.
Sounds like you have it narrowed down. I used to see lots of the coolant level senders fail when they were in the upper rad hose. Even with the coolant only being a little bit low, the sensor would indicate low coolant, and shut off the machine.
I sure appreciate all the help. Still puzzled why it wouldn't start without K plugged in. Now I did pull all three plugs. Should probably left the smaller ones plugged in and just removed the bigger center one, that had GB in it. One thing for sure, I sure know a lot more about how they work ! Thanks again Gary and thank you to this forum.
No problem. Its also left me a bit confused as to why it doesn't run with the relay unplugged. Good luck finding your issue.