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Most gauges not working right...??


86RangerXL

Well-Known Member
Joined
Feb 28, 2022
Messages
45
City
Tallmadge, OH
Vehicle Year
1986
Transmission
Automatic
Just as a little backstory, I picked up this 86 Ranger with the 2.9 in it and when I first brought it home, the temp gauge didn't work at all. I replaced the coolant temperature sensor and now it kind of works...?

When starting the truck, all of the gauges move VERY slowly to the normal positions, the gas gauge is really inaccurate, the temp gauge only goes to about 1/4 of the normal operating temp and never goes higher than that even when driving it for 30+ minutes, and the ammeter just sticks in the middle and doesn't move at all no matter what. I'm not sure if the oil pressure gauge works right since all of the others aren't, but when turning on the truck, it goes to the exact middle of the gauge and sits there. I was talking with my dad about this and he said it could have to do with the voltage regulator. Any ideas?
 
He's talking about the constant voltage regulator in the dash, not the one in the engine compartment. It has a plug connector similar to a 9v battery. A constant voltage regulator failure would make the temp, oil, and gas gauges all seem to read either low or high. Ammeters never moved much so that may be normal, either way it doesn't run off the CVR.
 
Take off the wire on the temp sender you put in
Turn on the key, see what temp gauge does, should go HOT or stay at COLD
Now ground that temp sender wire to engine or battery negative
Temp gauge should now do the opposite of before, full HOT or full COLD
If so then voltage in dash is OK, if it doesn't go full one way or the other then voltage is not OK


AMP meter is a separate device as said above
It uses an electrical shunt on the alternators B+ wire
A shunt is just a smaller wire so only 5%-10% of the alternators amps will flow thru it
It shows the direction of travel of electricity/AMPs
C or "+" means electricity is traveling from alternator TO the battery, charging battery
D or "-" means electricity is traveling from battery TO alternator, so draining battery

When people put in newer generation alternators the shunt is often removed which disables AMP meter

Use a Volt meter to test battery, engine off, 12.3v to 12.8v is expected
Then test battery with engine running, 13.5v to 14.8v is expected, alternator is working
If voltage is the same as engine off then alternator is not working, battery is being drained
 
Reply
Take off the wire on the temp sender you put in
Turn on the key, see what temp gauge does, should go HOT or stay at COLD
Now ground that temp sender wire to engine or battery negative
Temp gauge should now do the opposite of before, full HOT or full COLD
If so then voltage in dash is OK, if it doesn't go full one way or the other then voltage is not OK


AMP meter is a separate device as said above
It uses an electrical shunt on the alternators B+ wire
A shunt is just a smaller wire so only 5%-10% of the alternators amps will flow thru it
It shows the direction of travel of electricity/AMPs
C or "+" means electricity is traveling from alternator TO the battery, charging battery
D or "-" means electricity is traveling from battery TO alternator, so draining battery

When people put in newer generation alternators the shunt is often removed which disables AMP meter

Use a Volt meter to test battery, engine off, 12.3v to 12.8v is expected
Then test battery with engine running, 13.5v to 14.8v is expected, alternator is working
If voltage is the same as engine off then alternator is not working, battery is being drained
Thanks a ton. I tested it that way and the voltage regulator must be bad since I unplugged the temp sensor and the gauge only moved like 1/5 of the way up.
 
He's talking about the constant voltage regulator in the dash, not the one in the engine compartment. It has a plug connector similar to a 9v battery. A constant voltage regulator failure would make the temp, oil, and gas gauges all seem to read either low or high. Ammeters never moved much so that may be normal, either way it doesn't run off the CVR.
I can't seem to find one that says it fits a 86 Ranger. All of them say nearly every Ford model except the Ranger and Bronco 2, like this one. https://www.dennis-carpenter.com/tr...ry/d1az-10804-a-instr-cluster-voltage-regulat
 
I can't seem to find one that says it fits a 86 Ranger. All of them say nearly every Ford model except the Ranger and Bronco 2, like this one. https://www.dennis-carpenter.com/tr...ry/d1az-10804-a-instr-cluster-voltage-regulat
That looks like what you want to me, it's the same part number Andy B posted. I've never found a good aftermarket one and the last Ford one was about $35. They used to be $3,they're just a mechanical regulator someone should have come up with an electronic replacement by now but I haven't found one. It needs to deliver 5 1/2 pulsating volts.
 
The part number is d1az-10804-a

I’d check eBay and rearcounter.com
That looks like what you want to me, it's the same part number Andy B posted. I've never found a good aftermarket one and the last Ford one was about $35. They used to be $3,they're just a mechanical regulator someone should have come up with an electronic replacement by now but I haven't found one. It needs to deliver 5 1/2 pulsating volts.
Alright, thanks. I'll order it and see if it fixes the problem.
 
Reply

Thanks a ton. I tested it that way and the voltage regulator must be bad since I unplugged the temp sensor and the gauge only moved like 1/5 of the way up.

On the first gen trucks, removing the wire from the gauge sender and grounding it should peg the gauge full hot, unplugging it will cause it to remain at the bottom of the range.

That looks like what you want to me, it's the same part number Andy B posted. I've never found a good aftermarket one and the last Ford one was about $35. They used to be $3,they're just a mechanical regulator someone should have come up with an electronic replacement by now but I haven't found one. It needs to deliver 5 1/2 pulsating volts.

I know the early Bronco suppliers are selling an electronic regulator, they don't pulse the voltage but they come up to about 5v, they were around 30 bucks the last time I checked. the pulsing causes the gauge to come up to position more quickly and that's about it. I made my own regulator from jellybean electronics parts about 15 years ago and it's set at 5v, gauges work fine. if you're reasonably good at soldering you should be able to make something like this out of a commonly available USB car charger and a 9v battery connector. Disassemble the charger, add wires for 12v in and 5v out, heat shrink up the board and wire it in, you should have all of the connections you need at the back of the cluster. if memory serves me correctly, the regulator will have a +12v input and a +5v output connection and should be chassis grounded at the screw securing it to the cluster (can't remember if it is or isn't, it's been a while)
 
Ok, and to be clear this regulator supplies the 5 Volts to only Temp and Fuel Gauges?
Because those are the two that are not functioning on my 90 B2. thanks!
 
Ok, and to be clear this regulator supplies the 5 Volts to only Temp and Fuel Gauges?
Because those are the two that are not functioning on my 90 B2. thanks!
yes, also oil pressure gauge I believe
 
I have been researching this, it seems there is also an Anti-Slosh module that is problematic… I am going to open up the instrument cluster and have a gander.
 
I have not installed it yet, I bought a (voltage) buck converter off E-Bay. Rated for 2 amps, I am going to hook it up and see how it does at 8-9V which I believe is the spec., not 5 volts.
 
did it Work?
Sorry for taking so long to respond. The actual regulator took a while to get here and then I just didn't get around to installing it. But sadly, it didn't fix it. I still only get 1.6v to each of the gauges. I noticed my old one has an extra pin below the bigger connector and also a copper strip coming off of it, but the new one doesn't have either.??? Plus, the new one was completely flipped backwards too.

EDIT: I just went back and tested it, and 12v is getting to the IVR and 5v is coming out of the IVR so the regulator is working how its supposed to. Something else must be happening between the regulator and the gauges
 

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