Cougar

It was the pickup inside the disty. You proved the coil was okay. Now you will see a pulsing light on the negative side of the coil if you put a test light on it as the module inside the disty grounds the circuit and turns off the lamp, and that action fires the coil.

The newer audio and navigational systems can draw significant current from the battery so keep the run times while the engine is off to a minimum. I think the normal current draw is around 8 amps for the newer systems.

Even though the voltage differences you read are small I think it indicates the problem is with the ECU. The two sides are basically mirrored circuits and should have the same readings voltage wise and ohm wise.

Make sure fuse 5 is good and has power to it.

How do the two voltages of the two wires compare to each other? If the ECU is okay they should be close to equal. I would suspect dirty switch contacts for the door lock issue. The driver side is usually the best suspect.

I have heard of a 12 volt outlet in the rear but not a 9 volt outlet. From what you say it seems the battery connections may be loose or the battery charge is weak. Make sure the connections are clean and snug tight, not over tight. If the headlights are dim try charging the battery for about 2 hours.

I think you have pretty much proven that the ECU is at fault. I suggest you check to see if you can get a replacement from a salvage yard at a real reasonable cost.

It does sound like the alternator has a problem. Even though the DC voltage is slightly low the AC voltage should also be checked across the battery while the engine is running around 1,500 RPM to see if excessive AC ripple voltage is getting to the battery. This could explain the smell you noticed and may be coming from the battery. AC ripple voltage should be less than.1 volt. Have a load check done on the charging system to check the condition of the system.

Some other tests you could make to verify the ECU as the trouble is to compare DC voltages on the two wires going to the ECU while the ignition is turned on, using ground as reference. See if they are the same readings. Also check the two wires with just the ECU connected to the wires and do a diode function test referenced to ground and swapping the probes to check both directions of the current, with the ignition switched off. See if those readings compare to each other. They should be close to the same readings if things are good inside the ECU.

If you still have the timing covers off check the reluctor fins on the crankshaft and make sure none of the tabs have broken off. This has happened to some folks with this kind of problem. If they are okay then it would seem the ECU has to be at fault.

I think you nailed the issue in your last sentence of post 3 and it was what I was thinking of before I read the post. Corrosion under the main fuse panel. Water has gotten to it and caused connections to be bridged together that shouldn't be. Get to the bottom of the panel and clean it up. You may have to replace it if it is really in bad shape.

From what you stated earlier it appears the red/grn wire is open. There is a gray, 16 pin connector, B22/E3 near the center of the engine that the wires pass through. The trouble is most likely at that point. Disconnecting and reconnecting the connector may solve the issue.

The reason you can't take a resistance reading when power is applied to a circuit is because the meter supplies power to it in order to make the test. Adding additional current in the circuit will throw the reading off. Checking for voltage across a suspected bad ground connection while there is a load on the circuit is the best way to find a ground problem. I suggest you try testing the circuit operation for the knock sensor. Remove the connector to the sensor and install a 510k ohm 1/2 watt resistor on the connector end in place of the sensor. If there is a singe wire going to the sensor then you will have to ground one end of the resistor. See if the CEL light goes out then. If it doesn't then the ECU may have an internal problem with that circuit, though having the correct bias voltage is encouraging.

As the others have already stated, the trouble is most likely due to one of the rear dual filament bulbs. One of the two filaments inside the bulb can stretch and come into contact with the other one. I think the running light filament is the culprit normally. When the two bridge together then the voltage for the brake lights passes on to the running light circuit which back feeds to the interior lights. As "jono" also correctly pointed out this kind of thing can happen to the trailer wire harness connections if corrosion gets to the connections. Using the wrong bulb was mentioned by others and that will do it also. I assume things worked okay after you replaced the bulb and then had trouble later on so the correct bulb seems to have been installed.

I think Fairtax4me has a good idea on the timing belts. Doing a compression check might show the issue.

The reason the coil got so hot was because the minus side of the coil was mistakenly tied directly to ground. The coil windings could very well be damaged due to that mistake.

It sounds like you had a ground wire incorrectly connected to the minus side of the coil and if so that is why the coil got hot. Excessive current flow through the coil windings. You may have damaged the coil windings by doing that. If you haven't already replaced the coil after removing the ground wire I suggest you do that. To see if the disty is working correctly use a test light probe and place the tip on the minus side of the coil. Then crank the engine and see if the light flashes brightly while the engine is turning over. If that is good then either the coil is bad, the coil wire is open, or the igniter module is bad.

The links might be inside a plastic box mounted on the coolant reservoir. The later models were there at least. They should be near the battery anyways.

Okay, here we go. There is a red wire going to pin A1 of the dash fuse panel that supplies power to the front lights from fuse 5. The problem could very likely be a splice connection under the fuse panel so check for power on the wire. If there is power there then there is a most likely a break in the wire going the lights. Very possibly at a connection point. Check the red wire at the light also. If you have power there then the trouble is most likely a bad ground connection. If you can make a test light glow dimly on the ground side of the light then there is a bad ground to the front parking lights.

Placing a test light probe on the minus side of the coil should make the light flash brightly while cranking the engine if things are good. If the light stays on steady or there is no light then either the module inside the disty is bad or voltage isn't getting past the positive side of the coil.

Another thing you can do is verify that voltage is getting to the motor when any speed is selected and the ignition is ON. You should have voltage on both leads of the motor if the relay and wiring is good to the motor. The resistor pack is on the return side of the motor circuit.

The trouble could be due to an intermittent problem with the ignition system. You could keep a can of starting fluid inside the car to have on hand if the problem returns. If spraying a little amount of the fluid (a 1 second shot) into the intake makes no difference in the engine cranking over then the ignition system is suspect. I think the '97 2.5 liter engine is an interference engine and if that is what you have you are living on borrowed time if the timing belt wasn't replaced before now. If it breaks you are in for a pretty big repair bill.

You make another good point Ivans Imports. If the OP hasn't verified the disty is turning while cranking the engine that needs to be done next. If that is okay then going from what was stated in post 11 it indicates that either the wiring from the disty or, the control unit shown in the above parts view is bad. I think it is the only thing left in the circuit that hasn't been replaced.

Replacing the disty with a good used one may be the easier way to go with this.

A slight dimming of the headlights is normal. The alternator output drops down slightly at idle speeds so voltage at the battery also drops down some. What you are seeing is most likely from that but it is good to go over connections and clean them just to be sure they are okay.