Ladybug83

Well, me and my better half have been on a 10 day "cleanse" diet for the past 5 days, and while it is working (lost 10lbs so far!), it is also miserable. So, this holiday weekend we will be avoiding all bbq's, party's and anything where we might encounter food and beverage.

To add to the misery of not eating food, I thought I'd try to tackle a couple electrical gremlins that have been persistent regardless of my efforts thus far. I have three gremlins, and three days to diagnose and fix them. Seems reasonable.

First gremlin is the oil level light on the dash gauge. Comes on when RPMs are increased past 1,600 or more. I've been reading some suggested threads and troubleshooting guides and it seems like there could be a few culprits based on the past experiences of others. Some resolved the issue with a new alternator, some with a new voltage regulator, some with a new dash bulb and/or resistor on the back of the gauges. Broken blue wire or dirty grounds isn't a problem. The harness is new and all grounds have been double checked for cleanliness and tightness. I've armed myself with all of the new parts with the exception of the resistor. I didn't feel great about the aftermarket alternator that came with my car so I got a rebuilt Paris Rhone from 928Intl. I like the idea of re-installing the original ducting and the housing on the back of the alternator, which was not present with the aftermarket unit. Good or bad, the aftermarket is coming out. After that, if the light is still flashing at high RPMs, I will open the pod and inspect the bulb, resistor and the associated connections. Sound like a good strategy?


Second gremlin is the coolant level light. Comes on immediately and stays on indefinitely. Picked up a used sender from 928Intl, installed and same thing with light, On. Unplugged, light goes off. Wires shorted together, light is on. First thing Ill check is the ohms across the sender contacts. Other than that, Im kind of at a loss for direction. Not sure if there is a short in the wiring somewhere.

Ive been studying the wiring diagrams. WSM page 97-175. Seems like the coolant warning light shares the same circuits as some other components, such as the turn signal. Currently, all of my front lights (turn signals, fog lamps, headlamps, etc) are all disconnected. I checked the loose ends and they are all insulated and not touching each other or anything else. Not sure if this would effect the coolant sender. I checked fuse 12, good. I checked the connections at plug H, looks clean and solid. I have one relay missing for the intensive washer system, which I see shares the same circuits (15, 30, 31) as noted at the top right lines of the page in the gray CE panel area. Any insight as to where else to look would be greatly appreciated.


Third gremlin is the shift indicator arrow light. It's always on. I can't find reference to it in the WSM diagrams. Any insight on where to start with this would also be greatly appreciated.



Meanwhile, Ive taken the car out for a couple short spins around the neighborhood since getting it all operational. All systems seem to working well. No fluid leaks. Fluid levels are full and stable. Starts quickly every time cold or hot. Im stoked, but Ill feel really good if I could get the lights to behave correctly on the dash.

Also, not sure if it's noteworthy, but I haven't noticed the heater valve operating no matter which position I switch the head unit to. These observations have only been when the engine is cold. Does it actuate once the car is warmed up? Could it be related to the coolant light on the dash? Vacuum was good when checked, but Ill check again for good measure.

Also have noticed the A/C condenser fan hasn't come on yet, cold or warm engine. The AC system is complete with new seals, but it is empty and has not been leak tested or filled with R12 yet. Probably not related but I thought Id throw it out there just in case.

Anyhoo, I hope everyone has a great holiday weekend and thanks in advance for any insight.

Josh

Ladybug83

Well the weekend was fairly productive.

Gremlin issue 1 (oil level light/exciter circuit) has been solved. I replaced the rebuilt Bosch alternator with a rebuilt Paris Rhone unit. After the installation, I tested voltage at the battery and at the jump post and I got results of 14.7 at both locations, but not at initial idle, only after the car has been revved above 2,000RPM. Indicator light on dash voltage gauge still not coming on when key is turned. So I proceeded to dismantle the pod. Sure enough, the indicator bulb was burnt out. I soldered a new one into the little mini circuit board and plugged the gauges back in. Indicator light now comes on when key is turned, and stays on continuously. Charging still indicates 14.5-14.7 at jump post and battery, but only after revving engine. Stumped, I dove back into the wiring diagrams. Noticed the bridge indications on plug "Z" on the CE panel. Closer inspection revealed that the bridge was plugged into the wrong pins. After repositioning the bridge to the proper pins.....Back in business! Indicator light comes on when key is turned to on position, turns off when the car is started, charging indicates 14.5-14.7 at jump post and at battery on initial start up! Nice to get this one solved. There are few threads on this topic, but none mention the position of the wire bridge at the CE panel, maybe the easiest thing to check in the system, and a good FYI for future detectives.

Gremlin 2 (coolant light) is still persisting. Removed and tested the tank float with the ohm meter and it seems good (0 at rest, .5-.6 when in floating position). Terminals are clean. Tested float in water and it floats without issue. I checked the wiring terminals on all of the sensors and they seem good, all new. So Im kind of stumped on this one and how to proceed with the investigation.

Currently Gremlin 3 (shift indicator light) will wait. Couldn't find any threads on this topic, can't seem to find reference to it in the wiring diagrams. Not super concerned about this one at the moment. Doesn't seem too critical.

z driver 88t

Josh, Please keep this thread updated if you track down any info on the shift light. That is the ONLY thing on my car that doesn't work and has always just intermittently flickered but is mostly off. It's been that way for 7 years that I've had it and never have seen any posts on RENNLIST for trouble shooting.

There are only a handful of threads on trouble shooting this when I use "search" and the system seems to be fairly complex in operation. Much more so than you would think.

Ducman82

how is the wiring TO the coolant level sender? not just the ends.... but the harness its self...

Ladybug83

I will.

Ladybug83

Seemed good when I went through it when the engine was out. I'll have to check it again. I wonder if I missed a ground wire. I ran it up to warm yesterday. Did not overheat, heater valve opens properly, fan comes on when warm. Level is good cold and warm. Seems to be operating properly. Is there any other source for the warning light other than the level sender? I know the later cars have a pressure sender but mine does not. Wondering if any of the temp sensors would set it off. From what I read, seems like only the level sender and pressure sender will set it off. Level sender tested good. Which leads me back to grounds. Hm.

Ducman82

i have never heard of later cars with some kind of pressure sender for the water jacket.... huh.....

could be a ground...

Ladybug83

From what I read, the coolant pressure sender is about 5" in front of the expansion tank, but only on later cars, 85+IIRC but don't quote me.