3 electrical issues, but it running!
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Logistics Pro
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From: Connecticut
3 electrical issues, but it running!
84 F150, 302 4-sp, The P.O. cut the wire to the dash pot on the 2v carb, I have no "indicators" to where it goes. Any one know?
My parking brake light and buzzer stay on, even when parking brake is released. Is there a replaceable switch on the E-brake pedal?
Three dash gauges don't work, Oil, Temp, Gas......But Amp works. What's up with that, Could all three sensors go bad? how to test?
Can I test actual gauges? how?
Thanks
Reamer
My parking brake light and buzzer stay on, even when parking brake is released. Is there a replaceable switch on the E-brake pedal?
Three dash gauges don't work, Oil, Temp, Gas......But Amp works. What's up with that, Could all three sensors go bad? how to test?
Can I test actual gauges? how?
Thanks
Reamer
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From: Denver Metro Area, CO
That BRAKE light is also an indicator of a problem in the brake system as a whole. Crawl down to your parking brake pedal, locate the switch on it adn disconnect the single wire (grounding that wire will make the light come on). If the dash light still comes on with that wire disconnected, you have different problems with the brake system.
Dash gauges... do the radio, wipers, heater fan also not work? Try turning the key lock a bit towards yourself, those mechanisms stick and may not always fully spring back to RUN from START.
Dash gauges... do the radio, wipers, heater fan also not work? Try turning the key lock a bit towards yourself, those mechanisms stick and may not always fully spring back to RUN from START.
FTE Legend
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From: Northeast, OK
Chris has you on the right path. You can test the gauges, but with three out of three dead I'd bet it isn't the individual gauges but something common. To test the gauges turn the key on and ground the wire at the sending unit. IOW, pull the wire off the oil pressure sender by the oil filter and ground it. The gauge should slowly swing to full scale. Same thing on the temp sender, in the intake manifold I think, and the gas gauge.
However, that isn't likely to be it. More likely is a fuse or the connector into the instrument printed circuit board, or even the Instrument Cluster Voltage Regulator.
However, that isn't likely to be it. More likely is a fuse or the connector into the instrument printed circuit board, or even the Instrument Cluster Voltage Regulator.
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From: Northeast, OK
Good point. That would do it for sure. And with this cold weather the grease would resist the spring and cause the key to stop short of Run. I had that exact problem on Dad's truck when I first got it. Turn signals didn't work, clock didn't work, gauges didn't.....
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Logistics Pro
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From: Connecticut
Radio and Radio light, wipers work.
Dash lights, Gas, Oil, Temp, do not.
With the brake light, pulled the wire, Actually broke on me, but BRAKE still lit.
Will check master cyl. (when a bit warmer)
Does anyone have the Parking Brake Switch part number? (not brake pedal switch)
Thanks
Dash lights, Gas, Oil, Temp, do not.
With the brake light, pulled the wire, Actually broke on me, but BRAKE still lit.
Will check master cyl. (when a bit warmer)
Does anyone have the Parking Brake Switch part number? (not brake pedal switch)
Thanks
FTE Legend
Joined: Jul 2010
Posts: 32,875
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From: Northeast, OK
It looks like the original one (E7TZ 15A851-A) was discontinued and replaced by E9TZ 15A851-A, although I also see E9TB 15852-AA.
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E9TZ-15A851-A SWITCH ASSY. (PARKING BRAKE SIGNAL LAMP) Marked as E9TB 15A852-AA Fits 1984/89 pickups & Broncos Obsolete
Replaced E7TZ-15A851-A (marked as E7TB 15A852-AA) fitting 1984/87 pickups & Broncos
Green Sales Company CINCINNATI, OH 45237 (800) 543-4959 has 12 of the E7TZ variants
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Is that what the other column means? Marked as?
And, I just developed a cunning plan! Seeing that they started using the switch in '84 and assuming Dad's '81 parking brake pedal assembly doesn't have a spot for the switch, I'll swap in the '85 unit I have as I put the truck back together. Yes, the wiring probably isn't there either, but then the '85 harness would have it. Nice upgrade!
And, I just developed a cunning plan! Seeing that they started using the switch in '84 and assuming Dad's '81 parking brake pedal assembly doesn't have a spot for the switch, I'll swap in the '85 unit I have as I put the truck back together. Yes, the wiring probably isn't there either, but then the '85 harness would have it. Nice upgrade!
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The column is for descriptions, but the numbers after the pound sign(#) (if supplied) are the identifiers marked on the part itself.
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Logistics Pro
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Is the instrument cluster fed by 12 volts at the plug, then 12V actually runs through the gauges, then the IVR reduces to 5.4V?
Since the 3 gauges don't work, I need to see if voltage is getting to the Printed circuit bd. Fuse is good. Just need to know which bands on the start of the Printed circuit has what voltage (normally)
Thanks!
Since the 3 gauges don't work, I need to see if voltage is getting to the Printed circuit bd. Fuse is good. Just need to know which bands on the start of the Printed circuit has what voltage (normally)
Thanks!
FTE Legend
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From: Northeast, OK
I don't know what connections are what off the top of my head, but I should be able to get it tomorrow. However, the 12 volts goes to the ICVR and it turns it into 5.4 volts to send to the gauges and then on to the sensors and thence to ground.
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Thanks, Gary! I'd have left it to you but I already have a picture made out here.
All gauges except the ammeter are powered by the Instrument Cluster Voltage Regulator (ICVR) on the printed circuit.
Factory gauges operate at something around 5.5 volts, this is so their readings don't vary as the vehicle's voltage changes during normal operation.
The ICVR looks to be fed from a black/light-green-hash wire from the ignition switch (which has an inline resistor in it so voltage will already be somewhat reduced at the ICVR):
Factory gauges operate at something around 5.5 volts, this is so their readings don't vary as the vehicle's voltage changes during normal operation.
The ICVR looks to be fed from a black/light-green-hash wire from the ignition switch (which has an inline resistor in it so voltage will already be somewhat reduced at the ICVR):