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Re: STILL dying on decel... plus more performance issues Posted by Bill S [Email]  (#1209) [Profile/Gallery]
(more from Bill S) on Mon, 18 Mar 2013 17:21:26
In Reply to: Re: STILL dying on decel... plus more performance issues, RadioFlyer, Mon, 18 Mar 2013 14:01:33 Members do not see ads below this line. - Help Keep This Site Online - Signup |
Looking at the diagram a little more closely, on 88-90 cars the Park Brake and Brake Fluid lights are normally in "lights test" when the key is in "Run". They should both come on when the key is in "Start", and go off when the key is released to "Run" (unless the parking brake is set or the brake fluid is actually low).
Those lights are powered by pin 15 on the ignition switch, which gives voltage when the key is in either "Run" or "Start". The ignition switch relay is only powered in "Run". So, during "Start" the Park Brake and Brake Fluid lights are powered, and find a ground through the unpowered lights on the other side. When the key is released to "Run", the ignition relay energizes and puts system voltage on the ground side of the test circuit, so the lights should go out. This is similar to how the fog light relay grounds through the high beam circuit, so the fog lights go out when high beams are selected.
One question would be: if this why your Brake Fluid light comes on, why don't you also see the Park Brake light? Does your Park Brake light work?
If you turn your key to "Run" without starting the engine, do your alternator (battery symbol) and oil pressure lights come on?
I just thought of it: if power (from the ignition switch relay) to the LH side bulbs is interrupted (by, say, a broken trace on the mylar), if the ECU tries to throw up the CEL it will ground the Park Brake and Brake Fluid lights from the other side (and the CEL may not illuminate).
Having said all that, I think that what's going on is that when your instrument cluster issue is "active", the Brake Fluid light comes on when the ECU tries to put up the CEL. If so, the Brake Fluid light is not a clue to the cause of your running problem, it's just a symptom that's a compound result of the two problems together.
, Mon, 18 Mar 2013 11:24:11, Mon, 18 Mar 2013 17:21:26 <-- Viewing This Message, Mon, 18 Mar 2013 19:58:43, Tue, 19 Mar 2013 10:03:54
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