RickB et al:TD95D Warning lights at start up

Jerry/MT · Jan 20, 2011

With almost every modern vehicle I own, the warning lights come on at the beginning of the start sequence when the key is turned to the run and/or start position. On my TD95D, the only lights that come on are the Parking brake, the oil pressure light and the ammeter light. The directionals and light symbols come on when I turn their respective switches on but I never see the brake fluid light, the water in fuel light or the air filter delta P light.I seemed to remember seeing them come on when I went dow to look at the tractor before I bought it.
Further more, the owners manual does not even mention that these lights should come on at start to verify that the lamps are working. I can find no reference in the manual to what I'm supposed to see.

I checked the fuses that I thought were for the instrument panel and they were OK. I just spent 2 hours looking at the circuit diagrams and they make no sense. I know that the oil pressure light is on at start up and I tried to trace the circuit down to see where the power was flowing from knowing if I could do that I could figure figure out whether the lamps should be on or off. I traced from both directions and when I start at the oil pressure switch I end up at the turn signal bulb. If I start at the oil pressure light I end up at some other exterior light. Either I don't know how to read the diagrams or they are not correct.

I hate to keep coming back here with all these questions but does anybody know first should the lights be on at start up and, second, if they are, what's the potential problem? This machine has 100.3 hr on it and I'm sure some relay or timer or something is screwed up if the light are supposed to be illuminated.

RickB · Jan 20, 2011

I'm not gonna be much help here, but I think your tractor is functioning normally. The brake oil reservoir has a rubber button on top that can be pressed to manually close that switch to test the circuit. jbrink64 may come along and bail us out.

Jbrink64 · Jan 20, 2011

I'm pretty sure they are working correctly.

Jerry/MT · Jan 20, 2011

Jbrink64 said:
I'm pretty sure they are working correctly.

So they won't come on UNLESS there's a problem detected by the sensor. Thanks guys!

Jbrink64 · Jan 20, 2011

Hopefully they come on, when needed

RickB · Jan 20, 2011

Certain circuits with on/off senders that are normally open can be difficult to wire so as to self-test. Case in point is older Fords where the air cleaner sender is wired in with the engine oil pressure sender so both would self-test with key on/engine off. Apparently the Fiat engineers either didn't think a lamp test function was important, or couldn't figure out how to do it.

Jerry/MT · Jan 20, 2011

RickB said:
Certain circuits with on/off senders that are normally open can be difficult to wire so as to self-test. Case in point is older Fords where the air cleaner sender is wired in with the engine oil pressure sender so both would self-test with key on/engine off. Apparently the Fiat engineers either didn't think a lamp test function was important, or couldn't figure out how to do it.

It's done on cars all the time and I think those Italians know how to do it. It probably just drives some more cost into the circuitry and they are under "design to cost" pressure which is so prevalent in todays design world. The other possibilty is that they may feel the relaibilty of the bulbs(LED's?) may be high enough to not need a self test of the bulb. It just seems a bit strange to me. The implicatio in the owner's manual is that they only come on whe they sense a fault but it's a subtle hint at best.

But I sure appreciate RickB and Jbrink64 taking the time to respond. Thanks again guys.