The Stupid Electronics Questions Thread

[LTC_]

Checked voltage today. Seems okay. Red wire has 12v at all times and brown wire with ignition on. Took a look at the circuitry on the main board. All looks okay. Caps do not look blown and no burn marks anywhere. Guess I'll need to look for a new controller module.

 

[SUBURBAN5]

I know this is elementary. How can I wire the fog lights to light up both bulbs at the same time? Just like the headlight mod. Heres lmc's wiring diagram. What do I need or what can I change? Please if anybody can help me I really appreciate it. Also I rather not wire the lights to the headlights if possible. I prefer to keep this a separate circuit.

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[One eye]

Post here if you have a simple question. This will help keep track of common info and reduce clutter.

Tail lights will not shut off and blinker buzz's when either blinker is turned on. Installed new brake switch . Looking for trouble shooting sequence. Hope this is where I post new to forum .

 

[Erik the Awful]

The taillights come on when you turn the blinker on? Check to see if one of your bulb elements is broken and laying on the other element. Also check to make sure nobody's crammed a single-element bulb in a two-element socket.

 

[ThaEdge]

Well here we go... I purchased an all original 1996 one owner C3500 crew cab long bed 7.4L (its like driving a bus). The interior was not kept up, the rest of the truck is nearly perfect! So there are some issues I'm currently working through. I fgured I would try to save some time and ask around on here before I dive in chasing gremlins.

Issue 1: AC compressor won't engage. The sellars mechanic replaced a lot of parts that were worn and old, cahrged the system etc. and got it working but then less than a week later it stopped working agian. the seller took it back and the mech changed the control panel. that fixed again but then about weeks later it stopped working again. in that 2 week period the sellers wife died and he didn't want to mess with it any more so he sold it, to me. any suggestions on where to start digging?

Issue 2: cruis control doesn't work. when I got the truck the seller said it was working but when I drove it it only worked intermitently shutting off after a random amount of time, now it wont engage at all. the steering colum apears to be new. the seller didn't menchon that specificaly. he did say that he had spent about 12g's on the truck in the last 2 years with the AC, frontend rebuild, tires, tune up, etc. I was thinking break switch. any ideas?

Uodate: I finaly got some time and found the AC issue! took all of 5 minutes... It has no refrigerant. No pressure on the high side or low side. If anything it had a slight vacuum. So... Now to evacuate and see if she'll hold a vacuum. Here's hoping the shop forgot to charge the system (I don't have my fingers crossed).

 

[AK49BWL]

On the cruise: it COULD be the brake switch, but generally you'd see other issues when that happens (no TCC lock, brake light failures). My guess would be more along the lines of the module itself going bad (cold solder joints letting go or the gear solenoid burnt up), or maybe the multifunction switch in the column.

 

[Bacon_Drizzle]

**02/07/21 UPDATE**After about a year tracing this issue I finally found my issue with my #9 fuse blowing taking out my taillights, dash lights and parking lights. It was the wiring harness in my door panel with the window rolling up and down it started chewing through three of the cables exposing them to each other and blowing the fuse especially when I would shut the door close.

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[ThaEdge]

On the cruise: it COULD be the brake switch, but generally you'd see other issues when that happens (no TCC lock, brake light failures). My guess would be more along the lines of the module itself going bad (cold solder joints letting go or the gear solenoid burnt up), or maybe the multifunction switch in the column.

Ok That's what I was thinking. I just know some vehicles have more than one switch. I don't have any issues with brake lights or tcc lock. I did download the Service manuals so hopfully there will be some kind of trouble shooting procedure in there (though im not too hopful). Thanks for the input!

 

[LTC_]

Checked voltage today. Seems okay. Red wire has 12v at all times and brown wire with ignition on. Took a look at the circuitry on the main board. All looks okay. Caps do not look blown and no burn marks anywhere. Guess I'll need to look for a new controller module.

Just following up on this.

I found an HVAC controller in an 88 with 409k miles on it at the junk yard today. Plugged it in to my truck, and I now have working AC again.

 

[Wilecoyote]

I have demon in my dashboard.......Sometimes after a hard rain the radio/CD HVAC lights blink on and off and a crackling sound is heard when are all OFF. Now a month or more the blower box is making weird noises w the switch off, sounds like a mouse is scratching inside the box. If I turn the fan/heat/ AC on and the blower and the AC/heat works fine and no weird noises @ any speed from the blower and it blows low or fast cool/heat when adjusted. Now there's a crackling/scratching noise all the time when the the truck is running w no fan or heat or AC on. I know the windshield was replaced on the 98 K1500 and I wonder if rain is leaking under the dash. I can't find any wet spots under the dash or the floorboard but sometimes the glass fogs until I turn the defog on when it's cold. I'm also slowing losing coolant from the jug, but I don't smell any antifreeze in the cab w the windows shut. Any advice about this is appreciated.