NuclearBacon Posted February 24, 2006 Share Posted February 24, 2006 Ok so check this out.... I was coming home tonight, driving my newly resurected GL10, and all of a sudden i look down and my digital temp gauge is RED. like top bar red! i FREAK out, kill the car and let it roll to a stop.... i sit for a moment, turn my headlights off, and turn the key to the on position... the temp gauge is at the normal level... not thinking much of how the car COOLED OFF IN 3 SECONDS... i turn the key, starts beautifully *hehe* turn on my headlights and proceed the half mile home *my commute right now is 1.2 miles* within seconds BOOM! up to red again!!! AHHH!!!!! i kill it again. lol. i make it home, starting and stopping the engine... and head out using my stupid honda.... when i come back home again to diagnose the subaru, i get in it, and start messing around. finally i figure out that when the car is sitting idling... no headlights on, it registers perfect operating temp... when i turn the headlights on... 3 seconds later its RED... turn them off... BOOM back to normal.. and we're not talking like slowly climbing up and down.. it goes from 5 bars to RED back to 5. i then turned the engine off, and turned it to the ON position. got my temp reading, then turned the headlights on *with no engine running* and the gauge jumped 3 bars. so! how wierd is that! i looked in the FSM i have for my 87, and saw that it reads resistance to work... and on the analog gauge there is a type of voltage regulator so when the voltage changes in the car *because it does with design, if fans are turned on , or whatever* the temp gauge wont read anything different.... SO! what do i fix? is it a bad ground? if so, which ground is it? i'll scan a picture of all the grounds on the car if needed. is it... a bad temp sending unit?? is it the gauge? does the whole digi dash need replacing?! any ideas would be awesome. and i know ... i know! install a regular temp gauge. i will.. but i'd like to take this car somewhere and not be FREAKING out... or not ignoring the gauge. *scared* help! thanks! Quote Link to comment Share on other sites More sharing options...
Turbone Posted February 24, 2006 Share Posted February 24, 2006 Most likely bad grounds. My 86 turbo wagon does it also, but not to that extent. The more accessories you turn on the higher it goes. Oh, and its not a good idea to turn your engine off at high temps. You need toleave it running and hose down the rad to help it cool before turning it off. You could easily crack/blow something. Quote Link to comment Share on other sites More sharing options...
NuclearBacon Posted February 24, 2006 Author Share Posted February 24, 2006 Most likely bad grounds. My 86 turbo wagon does it also, but not to that extent. The more accessories you turn on the higher it goes. Oh, and its not a good idea to turn your engine off at high temps. You need toleave it running and hose down the rad to help it cool before turning it off. You could easily crack/blow something. yeah, but i didnt have a hose... and when i got out and put my hand over the engine, there was no excessive heat... nor steam.. or anything... it was just ... fine. so if its a bad ground, then which ground is it? should i post a diagram of all the grounds? thanks for your input! Quote Link to comment Share on other sites More sharing options...
subaru_styles Posted February 24, 2006 Share Posted February 24, 2006 couldn't abnormal voltage casue problems with the digi cluster? IE; bad voltage regulator. do you have a volt gauge or spare alternator to throw in there? Quote Link to comment Share on other sites More sharing options...
mikie Posted February 24, 2006 Share Posted February 24, 2006 Got a multi-meter ? havew a look and see if the voltage is bouncing round when you turn the headlights on, or maybe the alt starts over charging or something silly. Or a poor earth is causing big voltage drop somewhere thats giving a false reading. Quote Link to comment Share on other sites More sharing options...
Cougar Posted February 24, 2006 Share Posted February 24, 2006 I would suggest you make a about a 10 foot long ground jumper using at least a #12 gauge wire. Then tie one end to the negative battery post. Check suspected bad areas by placing the other end on a ground point and see if that cures the problem. I think the ground for the headlights is at the dash area so you may want to test that first. Quote Link to comment Share on other sites More sharing options...
Skip Posted February 24, 2006 Share Posted February 24, 2006 NB There was a TSB** issued around the time our cars were born that spoke of this problem. Their solution was to clean the ground for the dash board components, as suggested by others. This ground can be found under the front passenger side intake manifold bolt. Note: these steel bolts luv to corrode to the alloy manifold they pass through and can snap like a carrot when removed. A soak in PB Blaster (keep the WD for wet ignition systems) and some taps with a hammer might help. Cougars check of the headlight ground is also a good idea. This ground point can be found on the driver's side inner fender in the area behind the coil bracket.. Hope this helps and good luck. ** Technical Service Bulletin Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted February 25, 2006 Share Posted February 25, 2006 Interesting thing I've noticed - the non-digi's do that too. The more accesories I turn on in the Brat, the higher the temp guage goes, and the higher my fuel guage goes. Turn stuff off, and I lose heat, and fuel. Hehe. Has to do with the voltage being routed through the sending unit - more accesories = lower voltage for other stuff. Bad grounds will certainly make the problem worse/noticeable. Hey Skip - where do you find a listing of the ground locations? Or do you just know from experience? GD Quote Link to comment Share on other sites More sharing options...
Skip Posted February 25, 2006 Share Posted February 25, 2006 GD, they are shown in the FSM Quote Link to comment Share on other sites More sharing options...
civilpd Posted February 25, 2006 Share Posted February 25, 2006 Eeeeeeasy now... Quote Link to comment Share on other sites More sharing options...
NuclearBacon Posted March 28, 2006 Author Share Posted March 28, 2006 so i have the FSM, and have cleaned off the 4 grounds under the hood, and one in the trunk (just cuz it was easy) and it didn't fix the headlight issue... i was looking at getting one of these grounding kits: http://cgi.ebay.com/ebaymotors/7-CENTRAL-GROUND-GROUNDING-BLUE-WIRES-CABLES-SYSTEM-KIT_W0QQcmdZViewItemQQcategoryZ33574QQitemZ8050507675QQrdZ1 20 bucks, *shrugs* any ideas? Quote Link to comment Share on other sites More sharing options...
Cougar Posted April 1, 2006 Share Posted April 1, 2006 I think the problem is still due to a bad ground and the ground you really need to repair may be under the dash. Did you try using my troubleshooting technic I posted earlier? You don't need to spend a lot of money on a new ground system. You just need to find the right ground connection that is causing the problem and repair it. If you find that applying a good ground wire between the battery and the dash area corrects the problem you could just run a new ground and not bother repairing the original ground. Quote Link to comment Share on other sites More sharing options...
Mr. Carb Posted April 1, 2006 Share Posted April 1, 2006 Sounds to me like the issue sounds like a bad voltage regulator for the instrument panel. It's not uncommon for them to die out like that. Quote Link to comment Share on other sites More sharing options...
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