Smoke under the dash

Hi,

I'm not sure which wires are overheating, so that is a tough call. However, here is what I would be doing: First, check the blower motor and make sure it isn't drawing too much amperage. Second, confirm someone hasn't put the wrong size fuse in the circuit. Third, a loose connection (plug) or poor connection will create heat. Check all connectors. Forth, make sure the system has a good ground.

I attached 3 pics below. The first one is the AC wiring schematic for the lever-type control. Pics 2 and 3 are for the push-button type. I'm not sure which you have.

Here is a link you may find helpful:

https://www.2carpros.com/articles/how-to-check-wiring

I hope this helps. Let me know if you have other questions.

Take care and God Bless,

Joe

Thank you. sir, how will I know that the blower motor is taking much current than expected?
Any test for that?

You could use a multimeter to check for an amperage draw. On most multimeters, there is an amperage setting. Use the meter to jumper between the power supply and the fan motor. I would expect the draw to be approximately 5 amps.

Let me know.

Joe

Okay, thank you.

Good evening sir, I have printed those diagram but they are blur, I don't know if you could help me divide the diagram so that I can have a clearer picture.

For the wires, do I need to remove the dashboard before I access the wires or I can access the wires without removing the dashboard ?

Hi,

You should be able to do this without removal. The blower motor should be accessible on the right side (under dash).

Pics 1 and 2 are for the lever-type control. I cut the pic in half, but I did overlap them to help you follow.

The remaining pics are for push button control.

I hope this helps.

Joe

Thank you sir.

Hi,

You are very welcome. I hope they help. If you have a chance, let me know how things turn out for you.

Take care and God bless.

Joe

Hi, I worked on the vehicle, I confirmed the fault by putting on the A/C while the vehicle is running after few minutes, I saw smoke from under the dashboard and power distribution center (fuse box) at the engine compartment. I traced the wires, three different wires were stick together under the dashboard, I separated them. Checking the fuse box at engine compartment, I realized that the wires that powers compressor were completely burnt and some wires that comes from that big heater relay. I traced to know the cause before I saw that the A/C magnetic clutch wire at the compressor and one of the wires for the lock sensor were combine together.
Could that have been the cause of the burnt wire?
The wires are shown below.

I have replaced the burnt wires but the compressor is not engaging, when it is put on, the compressor will engage for like 5 seconds and disengage after that the light on the A/C button will be blinking, when the blower fan and A/C is turned off after sometime and turned on again, it will repeat itself. What could be the cause of that? I have a short video on that.

Hi,

Yes, the two wires in the first pic could have caused the issue, but the fuse should have blown before melting the wires. Check to make sure the fuse hasn't been replaced with one of a higher amperage.

Now for the light, does the compressor engage at first and then stop? The clutch itself may be bad. When the light starts flashing and the compressor stops, you need to check if there is power to the compressor clutch.

Let me know.

Joe

Thank you.

If I understood what you said, probing the test light at one end to the ground and the other end to the compressor wire, with the blower fan not in "off" position and the A/C button at "on" position,the test light should light up. For instance, if the test light illuminate but the compressor clutch does not engaged, then I can conclude that the compressor clutch is bad. Did I get it right?

In these situations, probing the test light at one end to the ground and the other end to the compressor wire, with the blower fan not in "off" position and the A/C button at "on" position, the test light would light up, at these point the compressor clutch will engage for few seconds (A/C button light will be steady). After few seconds, the A/C button light will be flashing,at these time, the test light will not light up (no voltage at the compressor), so the compressor will not engaged.
When turned off (the blower fan and the A/C button) for sometime and turned on again, the compressor clutch will engaged and disengaged after sometime as explained earlier (as shown in the short video clip I sent earlier).

I also realized that the wires of the compressor lock sensor has detached from the sensor at the compressor.

Hi,

Yes, it sounds like you are checking it properly. Have you tried repairing the wiring at the sensor? Did it make a change? Also, it sounds like you still have a bad connection causing power loss. Check back at the AC fuse and make sure it isn't getting hot.

Let me know.

Joe

The A/C fuse is that 10A fuse at the instrument panel according to the diagram, am I right?

Concerning the lock sensor, connecting the wires to the sensor (do I need to consider polarity or it doesn't matter)?

I saw it somewhere that the resistance of the lock sensor should be within 160-300 ohms, would it be advisable to connect a resistor of that valve across the wires (without the sensor) to know if it will function?

You called it a lock sensor. In all honesty, I never heard of a lock sensor for the AC. Could it be a pressure sensor?

The 10 amp fuse is for the AC switch. Power is supplied to the compressor clutch via the AC amplifier. See pic 1.

Joe

Lol,
If that is the fuse you were talking about, I have checked it, it seems to be okay.
If you check the diagram, three wires are going to the compressor, one to power the compressor clutch and the other two wires for the lock sensor. Check the diagram.

Those two wires that you traced at the compressor, that are white/blue and white/red are the wires that I am talking about.

Hi,

Those wires go to the AC amplifier. I indicated where they go below. As far as the fuse, I said it should have blown. I don't know why it didn't.

Okay, thank you sir.
I will get back to you sir.

Sir,

For the pressure switch how would I be able to bypass or check if it is faulty since it has four wires on it?

Hi,

You could run a jumper at the connector. However, check the pressure before doing that. Let's make sure it isn't already too high.

Joe

The pressure is okay. Using the jumper wire is not the problem but the wires that are to be jumped, most of the wire colors in the diagram is not the same as the ones in the vehicle. I just want to check if the pressure switch is good.

Hi,

If the wire colors are different, I'm not sure which to tell you to jump. I have the correct year make and model, so the colors should match.

Hi, as you said earlier that the fuse supposed to blown off before the wire start to burn. I checked the fuse at the instrument panel (10A heater fuse, looking at the top of the fuse, it is 10 amp fuse but it has wrapped with many wires, so I think that is why the fuse didn't blow off).

As I said earlier that two wires were not connected that goes to the compressor, I removed the alternator so that I can access the compressor properly but guess what! There I saw the real cause of the burnt wire, the black/white wire that supposed to power the compressor was naked somewhere close to the compressor and it do short the circuit to ground. After rectifying these everything works normal.

Thank you very much. I have disturbed you alot. You are a darling.

Sir, from the diagram the fuse (gauge fuse) supposed to be (heater fuse) because when I removed the gauge fuse all light on the instrument cluster went off and there was voltage at the compressor relay not until I removed the heater fuse (instrument panel).
Thank you

Hi,

I'm not sure why you would lose power to the compressor when removing the instrument panel or heater fuse. I have to ask, are you located in the US? If not, I suspect there is a difference in the schematics for different locations. That's the only thing that makes sense.

Let me know.

Joe

It is heater fuse that is among the fuses under the instrument panel not instrument panel fuse.
I am not located in US.

The schematic may show different colors. That is what it sounds like you are dealing with. Are you able to use the schematic to follow the wires? Not being there is going to make it nearly impossible for me.

Let me know.
Joe

I used the schematic to follow the wires but I didn't use the wire's color.

Hi,

It sounds like a problem within the fuse box. Is there any evidence of overheating, damaged wires, or connectors? That is the only thing that would make sense.

Let me know.
Joe