# New Holland TL90A Electronics Died



## NH Ed (Feb 4, 2021)

I have a New Holland TL90A and the electronics are totally dead on it. The dash lights and radio won't come on like normal when the key is turned on. the volt meter shows 12 volts on the battery and the monitors that are wired directly to the battery work like normal.
I have had issues with the electronics for a while. the brake warning light and buzzer come on at random times. there have been times when the dash lights went off for a second and then came back on and everything acted fine. Right before everything went totally dead, a few dash lights came on then went off again.
I can't imagine fuses are the problem since the dash lights have always come back on in the past but will check those.
Can this be (for lack of a better term) the mother board is bad?
Anyone had a similar problem?
PS-the dash light almost always shows the tractor is in 4 wheel drive even when it's not.
Thanks in advance for any help.


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## LouNY (Dec 15, 2016)

You may have a couple of inline fuses at the battery cable connectors.It is a poor place to have them because of the corrosion
that always seems to happen next to the battery. I'd suggest removing and cleaning your battery connections both positive and negative.
Then follow the main harness back towards the dash, disconnecting cleaning and greasing every connector till you get to the back of the dash.


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## BigT (Sep 15, 2014)

Attached link is for a TL90 Fuse Box diagram:









New Holland TL70, TL80, TL90, TL100 Fuse Box Diagram


Without a Cab With a Cab No. A Circuits Protected 1 10 With Power Shuttle: Power Shuttle circuit, (+ key) 2 5 Without Power




knigaproavto.ru


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## BigT (Sep 15, 2014)

If you were having problems with the dash lights sporadically going out, you may have a defective ignition switch.


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## NH Ed (Feb 4, 2021)

BigT said:


> If you were having problems with the dash lights sporadically going out, you may have a defective ignition switch.


Thanks everyone for your suggestions. I did clean the battery connections and had to replace the ignition switch about a year ago because it fell apart. Will double check it though.


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## Fedup (Feb 25, 2014)

Electrical problems are no surprise with those tractors. The parts list does show both a 40 and 50 amp maxi fuse on most serial number tractors. I'm not sure where it is, probably under a panel somewhere near the other fuses and relays. The lists posted above won't help much since the TL90A is quite a bit different from the TL90. I'm pretty sure the power feeds to the cab and instruments all stem from the starter solenoid post with the positive battery cable. 

As for a major "mother board" problem, I seriously doubt it. Yes the computer controls many of the electrical functions, but it has only a small memory circuit that's battery live. The rest gets turned on with the key same as the instruments. If the gauges, warning lights, bells and whistles don't come on with key on. it's more likely a connection issue in the power feed. probably below the instruments and in the fusebox/steering column area. 

As for the 4WD light on all the time, that's probably the pressure switch on the pressure line to the 4WD clutch drive. The clutch is spring loaded to 4WD and takes hydraulic pressure to disengage. That pressure (when present) opens the switch and turns out the light. If you crawl under the tractor and look at the lines near the drop box, you should be able to spot the pressure switch. It will most likely be wet and leaking while running. Those switches are known to leak when they fail.


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## NH Ed (Feb 4, 2021)

Thanks so much for all of your help.


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