JD 870 gauge problem
- Thread starter Bob Kern
- Start date
Are the instrument cluster lights working? Hour meter? Idiot lights?
If you have a voltmeter, can you check the voltage coming out of the voltage regulator? If it's too low or too high, it's not supplying proper voltage to each cluster item which can give no readings or false readings on the gauges.
If you have a voltmeter, can you check the voltage coming out of the voltage regulator? If it's too low or too high, it's not supplying proper voltage to each cluster item which can give no readings or false readings on the gauges.
Battery voltage with engine off is 12.6 volts, with the engine running just off idle it is 14.2 volts. The hour meter is inoperative but I believe it has never worked even when the guy I bought it from had it. It stopped at 1144.3 hrs. I've had the machine for maybe two years. The tach may have the needle missing. The two idiot lights for oil pressure and battery both go off immediately upon starting. The two gauges are both dead and make no movement at all. I am about to pull the fuel tank cover and see if the sending wire has power and/or continuity, and a good ground.
Sounds like the whole instrument panel is inop. I think there's a harness right behind the cluster and that may have an issue. Oil pressure and battery should go off once you start it but hard to tell from here if it's working as it's supposed to or is it a symptom of a cluster failure.
On further investigation I found that the tach drive cable end is broke at the engine pick up. That explains the no tach and hour meter cause. The sending unit feed wire at both the fuel tank sender unit and temp sensor at the engine, both have 4.2 volts with the key on engine off and both have continuity to ground. I'm thinking a bad float sender unit on the fuel gauge problem and maybe the temp sender too, but seems unlikely that both would go out at the same time. I can not find a fuel tank float/sender assembly for the compact series tractors anywhere, and it is not listed in my JD 870 to 1070 compact tractor parts catalog. Will call JD dealer tomorrow for part number. Have ordered a new tach drive cable.
I did an internet search for "JD 870 fuel sending unit" and got hits.
Don't know anything about this one or the seller but it's $95
Don't know anything about this one or the seller but it's $95
John Deere 870/ 970/ 1070 Tractor Fuel Tank Sender Unit | eBay
Find many great new & used options and get the best deals for John Deere 870/ 970/ 1070 Tractor Fuel Tank Sender Unit at the best online prices at eBay! Free shipping for many products!
www.ebay.com
Thanks. You pretty much need to undo and move the fuel tank a little to get the screws and assembly out. I want to pull the unit and check resistance values to make sure the unit is dead, before I spend a C note on it first. I'd like to get the part number to run a search on it also. BTW, I forgot to mention that the panel lights do work on the instrument panel too.