Back to original gauges

[AMC80cherokee]

Hi all! I am removing some aftermarket gauges from the top of my dash and trying to reconnect the original: oil pressure gauge, thermometer and etc. but I can't find of any these connections! does anyone know how the original oil pressure gauge works? because the aftermarket gauge has a hose (with oil) attached to it but I don't see any place on the original instrument cluster to connect a hose with oil...mine is a 1980 Cherokee WT.

[babywag]

The original gauges probably stopped working or are inaccurate.

Stock gauges are electric not mechanical, so no provision for the oil line.

You'll need to verify it still has the original sending unit and wiring connections on the engine.

Oil sender is by the oil filter and will have a single terminal for the original wire running to the cluster. Wire is blue IIRC.
Coolant sender is on the front driver's side of the intake manifold, again single wire connection, and wire is orange IIRC.

My advice is to keep the aftermarket gauges if they work.

[serehill]

Well

Unless someone cut them off there4 should be a round & one rectangular plug in the wiring harness that plugs intto the dash. If he cut them off get a copy of the manual & have fun. Like previously stated Original gauges are not accurate. If you are not sure at this point what's happening it will be very difficut to figure it out.

[joe]

You'll need the stock electrical sending units to run the stock gauges. The temp gauge has a CVR(constant voltage regulator) built into it to drop the voltage to the gauges. If your add-on gauges were installed because the temp gauge was bad I'd start with a brand new or at least a known working temp gauge. If the CVR is toast and the gauges get full 12V they'll all read wonky.

[AMC80cherokee]

Thanks guys! the aftermarket oil pressure gauge seems to be working but the temp gauge and voltmeter are disconnected...now that I know the colour codes for the respective wires; I think I can figure it out. I have an original (rebuilt) instrument cluster so I wanna use that. besides, the gauges on top of the dash looks ugly! because he had to punch a hole in the top of the dash .

Thanks again!

[babywag]

oljeep.com should have a wiring diagram set and a service manual that's close enough to '80 to work for gauge testing, specs, etc.

'73-'85 mostly the same when it comes to the gauges.

[Rich88]

Go here and scroll down to '80. http://oljeep.com/gw/elec/GW_wiring.html

Then go crazy & blind tracing wires from the sending units to the instrument panel plug to verify the correct wires & colors. See "8 cylinder" pages 1 & 2.

[Great Pharoah]

Guages

an 80 did not have a voltmeter guage in the original instrument cluster, it had an ammeter and I would be wary of that, especially if you have an aftermarket alternator. Any problem at all with it will burn up your cluster, then your interior, and finally your whole ride. Stay with a volt meter. You can mount it under the dash, or get on of those housing and mount it on the winshield pillar. you can get those in 1, 2, or 3 guage pods. Or you could get on of those replacement instrument panels from BJs and mount what ever you like.

[AMC80cherokee]

an 80 did not have a voltmeter guage in the original instrument cluster, it had an ammeter and I would be wary of that, especially if you have an aftermarket alternator. Any problem at all with it will burn up your cluster, then your interior, and finally your whole ride. Stay with a volt meter. You can mount it under the dash, or get on of those housing and mount it on the winshield pillar. you can get those in 1, 2, or 3 guage pods. Or you could get on of those replacement instrument panels from BJs and mount what ever you like.

The ammeter is in the original cluster and works fine; accuracy within 10% of actual - I measured the current with another independent ammeter. The voltmeter is in the 3-gauge aftermarket cluster and I can live w/o it. My only real concerns were the oil pressure wire/connection back to the OEM cluster and the temp reading gauge...

[Tinkerjeep]

HOLD ON! you will hear all kinds of crap about stock gauges being garbage. and for most people who don't want to get fingers dirty or scratched up, that's true, (I mean jeez most are 20 to 40 years old now!!!)

HOWEVER. You can get a manual and volt/multi-meter and do some resistance checking. You will want to remove the instrument cluster and perform these tests. Each gauge has a resistance value for its connections. Ammeter is a different animal. But your temp gauge houses the Constant Voltage Regulator which steps incoming 12-14volts down to about 5.5-6volts. The Fuel, Oil pressure and Temp run off this 5.5 volts.

Here's the deal. you will likely need to clean oxidization off the copper contacts and possibly the pins on the back of the board. this will help lower resistance and will make your gauges perform as intended...if the gauges themselves are functional.

Oil pressure sending units are available for $20 to $60 and screw on to the front passenger side of the block on the end of a pipe.

Temp gauge sending units are smaller and go into the back of the Thermostat housing or on the water crossover on the intake manifold...not sure on price.

Fuel gauge sending unit is in fuel tank mounted to float arm. not sure on price.

All the above sending units are electrical and rely on resistance to indicate accurately.

[Lindel]

The ammeter is in the original cluster and works fine; accuracy within 10% of actual - I measured the current with another independent ammeter. The voltmeter is in the 3-gauge aftermarket cluster and I can live w/o it. My only real concerns were the oil pressure wire/connection back to the OEM cluster and the temp reading gauge...

The issues with the ammeter is not it's accuracy, the issue with the ammeter is that it's a common cause of electrical fires in FSJ's. Not so much the ammeter as the 20+ year old wiring and the fact that people install bigger alternators or too many electrical devices.

A voltmeter won't have those issues, and will still tell you what you need to know about your electrical system without being a fire hazard. Far better to get the voltmeter and do the ammeter bypass.

[AMC80cherokee]

HOLD ON! you will hear all kinds of crap about stock gauges being garbage. and for most people who don't want to get fingers dirty or scratched up, that's true, (I mean jeez most are 20 to 40 years old now!!!)

HOWEVER. You can get a manual and volt/multi-meter and do some resistance checking. You will want to remove the instrument cluster and perform these tests. Each gauge has a resistance value for its connections. Ammeter is a different animal. But your temp gauge houses the Constant Voltage Regulator which steps incoming 12-14volts down to about 5.5-6volts. The Fuel, Oil pressure and Temp run off this 5.5 volts.

Here's the deal. you will likely need to clean oxidization off the copper contacts and possibly the pins on the back of the board. this will help lower resistance and will make your gauges perform as intended...if the gauges themselves are functional.

Oil pressure sending units are available for $20 to $60 and screw on to the front passenger side of the block on the end of a pipe.

Temp gauge sending units are smaller and go into the back of the Thermostat housing or on the water crossover on the intake manifold...not sure on price.

Fuel gauge sending unit is in fuel tank mounted to float arm. not sure on price.

All the above sending units are electrical and rely on resistance to indicate accurately.

I am in complete agrement regarding the gauges. Regardless of the original build-quality, after 20/30 years of use, a lot could begin to go wrong...so yes; I did find that cleaning the connections and especially tightening the GND tab/screw at the back the cluster, allowed all lights and gauges to function...as for acuracy of the critical readinsg like oil pressure & temp. meter, the temp. reading can be easily compared to an after market independent meter. I just felt that making the original cluster gauges work again (as they once did) was better than simply giving in and going aftermarket...THANKS for your help.

[Tinkerjeep]

and here's a funny thing I found out yesterday...like "funny as in HOLY CRAP!"

I have been pulling wiring harnesses of my various donor Jeeps for years, last night I was going through them to pick the best bits to build a 1985 in-cab wiring harness and fuse-block into one compatible to 1976 wiper switch and wipers and be compatible with late 1970s plug-ends. I found one 1979 Fuse blosk with the heavy yellow and red wires melted. I found a melted headlight switch connector. I've had a fan-motor switch melt while I was driving. Looking at all this stuff, and the fact that the Wagoneer body on my daughter's 1976 Truckoneer project had an underdash fire, I'm willing to put the blame on MORE than just the ammeter for causing electrical fires in these things.

Good wiring and gauges can go bad based on years of use/ improper ground or bad switches. Everyone's electric tailgate woes as well as other observances is testimony to the fact that "Made in America" does NOT always mean "Good".

[Lindel]

Wiring wasn't a Jeep high point, of that there's no doubt. Low quality wire, under-sized wire and marginal connectors are just a few issues with Jeep wiring, has been the case for years, before and still to come.

[Tinkerjeep]

yarp. I did notice considerably fatter wires in certain circuits in the 85 harness.