1985GLWAGON Posted August 28, 2005 Share Posted August 28, 2005 What would I check to fix a oil warning light that won't light? I checked the bulb and connections in the dash all seem to be in really good shape. What is the sensor that it uses to light the bulb? (so I can see if the sensor will still light it) When I turn the ign on, all that light are the alt, egr, stop lamp, and brake fluid. I don't have a auto so no AT temp light, but the oil light, R. Gate Lock light, and ECS light do not come on. Does the R. Gate light only work on power-lock vehicles? I have manual locks. And I think going by the manual my car doesn't use the ECS light either, so those are accounted for I think, but no oil light. No real reason why I want to know, no problems with the car, I just want everything to work right, plus if there ever is a non-pressure related oil problem I won't be notified about it. Just got done soldering the mirror controls back to working order. And now I'm moving to the dash. My brights indicator doesn't light either. Thanks for any info! Link to comment Share on other sites More sharing options...
Cougar Posted August 28, 2005 Share Posted August 28, 2005 Have you swapped the bulbs that are not working with some others that are to make sure the bulbs are good? If the bulbs are ok then you will need to get a test probe and check the wiring with it to see where the voltage is being blocked to the bulb while the ignition is on. Also make sure the ground to the bulb is ok. Link to comment Share on other sites More sharing options...
1985GLWAGON Posted August 28, 2005 Author Share Posted August 28, 2005 Yeah, I tested all the bulbs and just to be sure I swapped different bulbs to different sockets and lubed everything with dielectric grease too. After I put her back together everything was exactly the same. I don't think it's a problem in the dash wiring, it looked brand new and although I didn't test everything the ones I did test had good grounds, I traced the oil light's wiring as far as I could and no voltage with ign. on. others around it did have voltage like they were supposed to. So what actually controls the light? Is there a ecu or something somewhere, or a sensor under the hood? I don't know where the wiring goes once it disappears behind the instrument cluster. Link to comment Share on other sites More sharing options...
Cougar Posted September 3, 2005 Share Posted September 3, 2005 My '88 manual shows that the oil sensor makes a ground to turn on the warning light. The power to the light along with others is supplied by a black/white wire that ties to a red/yellow wire through a connector and ties to fuse 12. Link to comment Share on other sites More sharing options...
edrach Posted September 3, 2005 Share Posted September 3, 2005 I might be off base here but on the EA81 cars, you have either an oil pressure guage or oil light (GL or DL models). If you have a GL you have a pressure sender; if you have a DL model, you have an idiot light; you don't have both. Any possibility that's the same case on your '85? Link to comment Share on other sites More sharing options...
1985GLWAGON Posted September 3, 2005 Author Share Posted September 3, 2005 I have both a pressure gauge and a light, but what I don't know is what sets off the light? Is it the pressure sender if it gets too low, or a seperate oil temp sensor or what? That's one of the things I've been wondering about, if the pressure gauge shows me the pressure then what is the light for? Manual just says if the light comes on then turn engine off as soon as possible, so maybe the light is just a redundancy to remind you to look at the pressure gauge? Link to comment Share on other sites More sharing options...
1985GLWAGON Posted September 3, 2005 Author Share Posted September 3, 2005 Sorry edrach, I just got what you meant, I guess I don't know, is the light not utilized on full-gauge cluster cars? I just assumed it still worked but I don't know, never thought about it that way. Link to comment Share on other sites More sharing options...
1985GLWAGON Posted September 3, 2005 Author Share Posted September 3, 2005 Just pulled out my owner's manual and it calls the light the "Oil Pressure Indicator Light", so looks like you're right, light must not be active on gauge-equipped vehicles. I just assumed they both worked like on my Audi but I guess a Subaru aint no Audi . Makes sense too, since I have a MT it just goes without saying that the AT temp light doesn't light up, so since I have a pressure gauge the pressure light doesn't light up either. Thanks guys! That pretty much cleared it all up! Link to comment Share on other sites More sharing options...
Cougar Posted September 3, 2005 Share Posted September 3, 2005 The way I think things should work is the light should turn on when oil pressure gets too low. It will do this by making a ground connection in the pressure sensor when pressure drops too low. Since you have both indicators I would check for the sensor to be tied to the oil line going to the pressure gauge. I may be wrong on this, but that is what I'm thinking the way it might be. You should be able to find the tap for the oil gauge fairly easily. If you don't see an electrical sensor tapped in also for the warning light, then I guess the light isn't used. Link to comment Share on other sites More sharing options...
1985GLWAGON Posted September 3, 2005 Author Share Posted September 3, 2005 I could only find 2 sensor wires at all and one is for the coolant temp sender and the other for the oil pressure sender, so unless the light comes on as a backup warning, I guess it's not used at all. Anyone else have a GL wagon that can confirm this? Link to comment Share on other sites More sharing options...
Cougar Posted September 3, 2005 Share Posted September 3, 2005 Perhaps your gauge uses a transducer to send a voltage to the meter and not pressurized oil to the gauge itself like was done in years past. Link to comment Share on other sites More sharing options...
1985GLWAGON Posted September 3, 2005 Author Share Posted September 3, 2005 Yeah, gauge is all-electric, no oil lines. What I thought was maybe the light comes on when the pressure sender reaches some critically low point. My owner's manual says it can be normal to have the gauge at almost 0 psi when idling, so maybe the light is a backup to let you know when pressure is really critically low, lower than what the gauge can tell you. The manual is for a GL specifically and doesn't have diagrams for an idiot light only setup like on a DL. It just says the oil light should light up when ignition is on, doesn't sound like it's an "if equipped" sort of thing, more like it should light period, regardless of model, So I still don't know for sure. But since there's nothing wrong with her otherwise I guess I'll just leave it be, I don't know what else I can do to find out for sure. Link to comment Share on other sites More sharing options...
subarubuddy Posted September 21, 2005 Share Posted September 21, 2005 Yeah, gauge is all-electric, no oil lines. What I thought was maybe the light comes on when the pressure sender reaches some critically low point. My owner's manual says it can be normal to have the gauge at almost 0 psi when idling, so maybe the light is a backup to let you know when pressure is really critically low, lower than what the gauge can tell you. The manual is for a GL specifically and doesn't have diagrams for an idiot light only setup like on a DL. It just says the oil light should light up when ignition is on, doesn't sound like it's an "if equipped" sort of thing, more like it should light period, regardless of model, So I still don't know for sure. But since there's nothing wrong with her otherwise I guess I'll just leave it be, I don't know what else I can do to find out for sure. well i can't tell you for sure, but i have a '92 loyale with the same problem. only i am also not so sure if its supposed to be that way either. i found this post by doing a search because i wanted to find out if it was equipped with both a guage and a light. the guage works but the light does not (if there even is one). i'm starting to think maybe you get either a guage or a light but not both, depending how the car is equipped. But sorry, this probably doesn't really help. Link to comment Share on other sites More sharing options...
82bratavenger Posted September 22, 2005 Share Posted September 22, 2005 My manual for my GL Brat says the non-guage DL has a light but that the GL is just the guage. You can check for the oil light sender right on the oil pump. Your preasure sending unit should be screwed in on the bottom and there is a large plug to the passenger side and up in line with the oil filter. This is where your switch for the light would be screwed in. ie. no switch, no oil light. Just the guage sending unit. This is how I understand it. I can't remember seeing an oil light ever lit up on any of my previous GLs. Anyone else on this Idea? Feel free to correct me if I'm wrong. Link to comment Share on other sites More sharing options...
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