if you cant remove the red, it is probably because your screen has a cast of red through it. This means you have to adjust your monitor. And a white halo is easy.

With your truck on a transparent background, hold down Ctrl and click on the image thumbnail of the layer, this will select the pixels in the layer.

Make a new layer and make sure that layer is selected. Then fill the layer with white. Place the layer behind the truck layer and then apply gaussian blur.

White halo. Btw, if you have it on a black background, the halo will ofc appear grey since the blur is creating a blend between white (solid) and transparent. So with the black there, it appears grey lol.

If you want there to be white then the blur, you can expand the selection before bluring it to create white pixels outside the border of the truck.