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| 88 GT rear emblem light and hvac blower have power with car off and key removed (Page 1/1) |
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Pearl88
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JAN 18, 03:56 PM
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Hello all, i recently installed a new heater core in my 88 GT. So im not sure if these issues I am going to list started before or after the heater core replacement. I only now noticed these gremlins when i came home after dark the other evening. The issues I am having is that my rear emblem or "pontiac" lights seem to be on constantly even with the car off and no key in the ignition. Also the hvac control head suffers from a similar issue in that i can turn the blower on and control all fan speeds with the key off as well. Finally once the radiator fan is activated it will continue to run until the engine temp is cooled down even with the key off. I have unplugged the rad fan relay during this to kill the fan but the other issues noted before remain with the relay unplugged. I have also disconnected every other relay you could imagine on the car except the fuel pump relay to see if one was stuck on. The main ignition switch is unplugged and the orange wire at the switch that i think should only have "run" power is currently hot all the time. I could be wrong on the wire function. Also of note is the car has zero modifications to the wiring for certain. My grandma bought it new in 88 so car has always been in the family so the history is known. oh and all fuses are new today. What am i missing?
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Vintage-Nut
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JAN 18, 06:59 PM
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| quote | | The main ignition switch is unplugged and the orange wire at the switch that i think should only have "run" power is currently hot all the time. |
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Do you mean that the orange wire is unplugged from ignition switch and the orange wire STILL has 12V?
Or you mean that the orange wire HAS 12V when plugged in the ignition switch at the off/lock position?
If the latter; your problem is a shorted ignition switch {the 'Run" position connectors are frozen}.
| quote | rear emblem or "pontiac" lights seem to be on constantly even with the car off and no key in the ignition
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This because the shorted ignition switch / the orange wire feeds Fan E Fuse at the 'Run' position and powers the 'Pontiac' bulbs
| quote | | the hvac control head suffers from a similar issue in that i can turn the blower on and control all fan speeds with the key off as well. |
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Same issue - 12v power is from the switch 'Run' position too / the orange wire feeds HTR A/C Fuse to the blower switch
| quote | | Finally once the radiator fan is activated it will continue to run until the engine temp is cooled down even with the key off. |
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This is normal
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Original Owner of a Silver '88 GT
Under 'Production Refurbishment' @ 136k Miles[This message has been edited by Vintage-Nut (edited 01-18-2025).]
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Pearl88
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JAN 18, 09:21 PM
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Yes both plugs are unplugged from the switch itself and the column is laying in the drivers seat. When I probe the orange wire pin in the connector it lights up my tester and shows 12v.
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Pearl88
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JAN 18, 10:08 PM
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Yes both plugs are unplugged from the switch itself and the column is laying in the drivers seat. When I probe the orange wire pin in the connector it lights up my tester and shows 12v.
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Vintage-Nut
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JAN 18, 10:40 PM
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| quote | | Yes both plugs are unplugged from the switch itself and the column is laying in the drivers seat. When I probe the orange wire pin in the connector it lights up my tester and shows 12v. |
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So, you're telling me that the orange wire is unplugged from ignition switch, and the orange wire STILL has 12V with the other probe on ground...
This means that the orange wire unplugged from ignition switch and has 12V AND the rear emblem "Pontiac" lights are STILL on...?
Remove two fuses from the fuse block:
*Fan E Fuse
*HTR A/C Fuse
The orange wire STILL has 12V with the other probe on ground: Yes or No?
Yes = check the window circuit breaker
No = check Fan E Fuse and HTR A/C Fuse for 12V at the inputs and outputs[This message has been edited by Vintage-Nut (edited 01-18-2025).]
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sleek fiero
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JAN 18, 10:48 PM
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Hi Vintage .My 85 GT has always from new turn the key off and the fan shuts off. Does only the 88 keep the fan running or is mine faulty all these years? sleek
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1985 Fiero GT
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JAN 19, 12:40 AM
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| quote | Originally posted by sleek fiero:
Hi Vintage .My 85 GT has always from new turn the key off and the fan shuts off. Does only the 88 keep the fan running or is mine faulty all these years? sleek |
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No, the radiator fan relay does get an ignition 12v signal, turning it off when ignition is off, not letting it turn on, etc. note that the stickers on the radiator say that the fan can turn on when engine off if key is on, doesn't need the engine to be on, just the ignition key.
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Pearl88
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JAN 19, 11:59 AM
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| quote | Originally posted by Vintage-Nut:
So, you're telling me that the orange wire is unplugged from ignition switch, and the orange wire STILL has 12V with the other probe on ground...
This means that the orange wire unplugged from ignition switch and has 12V AND the rear emblem "Pontiac" lights are STILL on...?
Remove two fuses from the fuse block:
*Fan E Fuse
*HTR A/C Fuse
The orange wire STILL has 12V with the other probe on ground: Yes or No?
Yes = check the window circuit breaker
No = check Fan E Fuse and HTR A/C Fuse for 12V at the inputs and outputs
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Ok pulling both those fuses kill the hot on orange. If either one are back in it is hot again doesn’t matter which fuse is in. Probed the fuse terminals with fuses out and the FAN E is hot on the right terminal if looking at the fuse block while it’s uncliipped and swung down. Nether terminal is hot for the HTR slot. The Pontiac lights stayed on the whole time doing those tests you mentioned[This message has been edited by Pearl88 (edited 01-19-2025).]
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Vintage-Nut
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JAN 19, 04:05 PM
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| quote | | Ok pulling both those fuses {Fan E, HTR A/C} kill the hot on orange. {GOOD} If either one {Fan E OR HTR A/C} are back in {in the fuse block} it {orange wire} is hot again {and} doesn’t matter which fuse is in. {Means both Fan E AND HTR A/C have voltage at the fuse output} Probed the fuse terminals with fuses out and the FAN E is hot on the right terminal if looking at the fuse block while it’s uncliipped and swung down. Nether terminal is hot for the HTR slot. {But you said "either one fuse" will power the orange wire?} |
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Obviously, you have a SHORT, first look for a short in the fuse block.
If no, disconnect the Generator/Alternator {both the big red wire and the 3-wire plug, and they're HOT from the battery}
If the 12V is GONE on the orange wire with the Fan E fuse in; replace the Generator/Alternator[This message has been edited by Vintage-Nut (edited 01-19-2025).]
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