Low Fuel and High Coolant Temp warning lights

[john keefe]

Trying to save a little time here... Occasionally the amber "empty" gas warning round light would come on, regardless of fuel level. Annoying, but tolerable. Now, both that amber light and the red light for overheating are constantly on (temp gauge reads normal), and won't reset off even if I cut battery power for 15 min. or so. Both some on KOEO, but don't shut off like the other indicators. Whacking the dash pad doesn't work.

I presume this is something in the IC circuit board, and not in the actual sensor wiring as both analog gauges are working fine. Any confirmation of that, so I'm not wasting time testing circuits and swapping sensors, etc.?

Thanks!

[PeterP11c]

Actually, on my Scorpio this was a sign of a failing onboard computer (the one sitting under dashboard passenger side). First it was one light, then another and another. I got a spare, took out the dash, swapped one for another and the problem went away. It may seem like a big time job, but in fact it's fairly straightforward, under one hour labor and no special tools are required.

[john keefe]

Thanks Peter. I'll look at a manual to see where and what it looks like. Gotta' get in there sometime anyway to fix the odometer gears.

[PeterP11c]

Oh, yes, you mentioned one of my hot topics. I did it once, took apart the instrument panel and cut away part of the clear plexiglass housing thus getting access to the odometer assembly. Put in the new gear and it worked albeit for a while. Once, I reset the trip counter, my odometer again stopped working . Don't know why it happened. Have in my storage another full dash unit, so one day I will tackle with this problem. The issue is with time, you have to dismantle the dash, disconnect all electrical connectors in the area and then play with odometer unit itself. My weekends are never long enough.
The module itself is shown on page 33-45-7 lower right corner. It sits on the right side below windshield and is easily accessible with dashboard removed.

[brokencase]

Definitely not a fun job changing the odo gear. I can't believe such a defect got past qc. Just about every Scorpio I have seen has had a failed odometer.

When I replaced mine it looked like the failure of the old gear was caused by lubricant that was incompatible with the original gear plastic.
The original gear was soft and just crumbled....as if it was made of hardened jello. I didn't lubricate the new gear when I put it in.

I hardly ever press the tripmeter reset. On those rare occasions when I do I make sure the car is not moving when I do so.

Can't help regarding the intermittent warning light issue. Have not encountered that type of error yet.

[PeterP11c]

Too bad they didn't design it right. I guess we are left to our devices, LOL. I did the trip odometer reset because every time I filled her up I calculated the average mileage and compared it with fuel computer reading. I hate to watch the odometer stuck as is, so the time is coming to sit down and repair it once more.

[Ed Lijewski]

I've done the odo gears replacement a couple of times (on two cars and two spare clusters). You don't have to cut out a piece of the light disperser although that could make it simpler; I chose to keep the light disperser intact. I borrowed Jeff Herson's test unit (made by Darren Needham) to verify the last gears replacement was working before installing the cluster in the dash. That odo stopped working a month or so afterward installation in the dash. My mistake was in not replacing the stepper motor that drives the odo gears even though the odo worked fine when powered by the test unit. Jeff says he stll has replacement stepper motors (he sent ne one earlier); for now I haven't taken the time to do that on that unit.

YMMV

[PeterP11c]

About this stepper motor, how complicated is this procedure? Any soldering involved?

[Ed Lijewski]

If you disassemble to get the gears out, the motor is readily accessible. One of the gears mounts on the motor shaft.

I can visualize the steeper motor-barrel shaped-but ATM can't recall its power connector. I did no soldering in this repair.

YMMV

[PeterP11c]

OK. Thank you. On the final note, do you recall the cost for the steeper motor?

[Ed Lijewski]

Jeff included it with the tester unit he sent me to use. I don't recall a price.


FYI from UK MKIII/Scorpio Face Book group.

Screenshot_20220214-133351_Lite.jpg (245.45 KiB) Viewed 4154 times

YMMV

[john keefe]

Thanks for the info, Ed. More ducks in a row for me, if/when I have time to get around to it.
Which brings up another question... I've got to "add" a few hundred miles to the odometer when its repaired to get back to current miles for smog purposes. Used to be you could just rig up a drill to spin the numbers (no, I'm not a slimy used car dealer ). How would that work with this mechanism?

[Ed Lijewski]

Build this signal generator, connect it to the speed/ometer unit, watch it run and add miles to your odometer until you're satisfied.

http://forum.merkurclub.com/forum/viewt ... t=Odometer

YMMV

[Ed Lijewski]

Just remembered that the stepper motor replacement part is like a rotor and just inserts into the stator of the stepper motor. When powered and receiving signals from the VSS, current flowing in the stator causes the rotor (barrel unit) to rotate in precise steps.

No soldering necessary, just remove and replace the barrel shaped rotor unit.

YMMV

Arrow points to barrel/rotor part.

20220214_140039_copy_1209x930.jpg (170.11 KiB) Viewed 4150 times

[brokencase]

Curious as to the failure mode of the stepper motor. Stepper motors are pretty simple. The gear I've seen fail, but not the stepper.

In any case this thread is getting sidetracked from the original problem regarding the warning lights. For which I will comment, clean connections to lamp warning module and see if that helps.