[unclemaui]

94 chevy astrovan all at once no speedometer. stays in low gear, windows, front and rear fans stop working a/c compressor does not start heater does not start.

I cannot find anywhere online about a relay or if it is the ignition switch that shuts off the accesories until the engine starts. (thinking shrot circut)

For grins and $47.00 I tried the speed sensor. still stays in low gear.

 

[RayVoy]

You have had a portion of the electrics fail. I didn't take the time to check your fuse arrangements, but you can do it. Dig out your fuse diagrams (the pics in the owners manual that show the fuse locations), locate each fuse and see if there is a pattern.
- Are they all in the same fuse panel,
- Are they close to each other,
- etc.

You could have a broken link in the fuse panel, you could have a broken/corroded wire providing power, or ground.

You could have a number of things.

Check out the fuse locations and report back

 

[unclemaui]

With the engine off or running all the components mentioned have no voltage [12v] the fuses are not blown. I have a good ground on all of them but no 12v

 

[RayVoy]

With the engine off or running all the components mentioned have no voltage [12v] the fuses are not blown. I have a good ground on all of them but no 12v

I know that. But, somewhere between voltage being turned on and components receiving power you have a problem. I am not there, so I am trying to suggest things to track down the common area. One small area is common to all. It could be an area of the fuse box, it could be a broken wire, it could be a bad ground, it could be a bad ignition switch. But, you need to track it down to find it.

 

[Big_Mike]

My dad has a 92 Astro and had similar problems. However, his instrument cluster stopped working once he turned on his a/c compressor (and no a/c if I recall correctly). He had a mechanic look at it and it turns out that a wire off of the ignition switch had a short in it, thus causing the malfunction. The mechanic wired the a/c system electrical circuit separately and fixed the problem. I don't know if this will help you, but maybe it will . I saw the post and it jogged my memory.