Caterham weirdness...

[Russ]

Yeah I know it's a British car, but some of the electrical behaviors exhibited by my Seven seem odd even by those standards. If anyone can explain the following, helpfully or not, I'd like to hear it.

1)Sometimes on first starting the motor for the day, the windshield wipers run for three sweeps. The obvious fix is to remove the windshield wipers.

2)The red LED on the speedometer seems to be "ignition", which near as I can tell is supposed to indicate the engine is running.

3)The tachometer lead from the wiring harness seems to only connect to a weak light bulb dangling under the dash which doesn't change brightness with RPM. It may be a backup for #2 near as I can tell. (Is tachometer controlled by voltage, pulse freq, or pwm?)

4)There's an electrical connector dangling from the left side under the dashboard which seems like it might be useful. It looks stock. Anyone know what it might go to?

5)The right blinker runs at twice the speed as the left. Probably a resistance mismatch somehow, but still funny.

6)TunerStudio software has gauges for all this and more, which work perfectly. Maybe it's easier just to mount a small digital screen above the steering wheel. It's not like I can see the speedo or tach when I'm driving anyhow.

[Lucky Dawg]

For #5, check to see that all of your right side bulbs are working when the signal is on. With mine, it is usually the one in the front wing.

[Russ]

#5: The front right indicator is weak, I suspect it is lighting either only one filament of two, or the wrong filament, but haven't checked yet.

Today I'm playing "What's tight that shouldn't be, and what isn't that should?" The throttle linkages are all loose with the locknuts spun up against the wrong end of the stops. I'll bet my low idle is a lot more consistent now.

[Doug Liedblad]

For number 4, is it just a spade connector? There is one on each side for the heated windscreen.

For #5 try using a flasher that uses a timer not resistance to control the interval. A search should turn it up.

[breezy7]

#2 sounds like the indicator for a charging system failure. My car had one but it never worked, I doubt it was connected. It should come on when you first turn the key on to check that the bulb is working and then go off once the car starts. If it comes on then the battery is not getting charged properly.

For #4 what engine do you have? My Zetec SVT had a connector under the dash on the left side that was used for the OBD II connection. A picture would help identify it.

[Doug Liedblad]

I agree with Breezy7, in my 2002 build the red light was to be the alternator failure light and it has never worked. I have never checked past past a visual check that it ain't a working. I installed a voltage gauge instead.

[Sean]

My alternator warning light does the same thing - always on when running. I understand from BC that this is a known issue with a proven solution. One day, I plan to install the appropriate 68ohm 4 watt resistor to correct this issue.

REF: alternator warning light always on solution

[moosetestbestanden]

My alternator warning light does the same thing - always on when running. I understand from BC that this is a known issue with a proven solution. One day, I plan to install the appropriate 68ohm 4 watt resistor to correct this issue.

REF: alternator warning light always on solution

ISTR from my reading of the wiring diagram during my project is that the instrument has a connection for a 3-wire alternator. No signal = inferred alternator failure which illuminates the LED. If you have a 1 wire self-exciting alternator or a 2 wire tickler type then the lamp will always be lit.

Edit: I would give the resistor a try but the MBE is feeding the alternator signal to my wheel mounted MBE instrument, which is conveniently blocking all of the analog gauges on the dash anyway.:-O

[Russ]

#4) Here's the connector:
SevenConnector_small.jpg

-russ

[breezy7]

That looks like the OBD II connector.

[Russ]

#4) OBD being "On Board Diagnostics" rather than "Old Dirty Bastard", it looks like an easy place to grab chassis ground, signal ground, and 12v.

[breezy7]

Yes for On Board Diagnostics. You can read engine fault codes if that ever becomes needed. I used the connector with a ScanGauge mounted to the console. It is a neat little device, if you aren't familiar with it, that will read fault codes and lets you monitor 4 other engine functions at once. I always kept the volt meter and water temp functions on the screen.