Custom postprocess white in build

I'm having some trouble with a custom post process i wrote for Unity. It's supposed to fade the colors of the scene using a color ramp texture according to depth. It works fine when I'm playing the game through the editor. But when I build the game everything is all white. So in some way my shader only gives white when running in a build but not in the play mode in the editor. I added my shader code below, the interesting rows are probably 34-37. Any suggestions?

 Shader "Custom/Tint"
 {
     Properties
     {
         _MainTex("", any) = "" {}
         _FogRamp("", 2D) = "white" {}
     }
 
         CGINCLUDE
         #pragma target 4.0
     #include "UnityCG.cginc"
 
     struct v2f
     {
         float4 pos : SV_POSITION;
         float2 uv : TEXCOORD0;
     };
 
     sampler2D _MainTex;
     sampler2D _CameraDepthTexture;
     sampler2D _FogRamp;
 
     v2f vert(appdata_img v)
     {
         v2f o = (v2f)0;
         o.pos = mul(UNITY_MATRIX_MVP, v.vertex);
         o.uv = v.texcoord;
 
         return o;
     }
 
     float4 frag(v2f input) : SV_Target
     {
         float depth = Linear01Depth(tex2D(_CameraDepthTexture, input.uv));
 
         float4 fogColor = tex2D(_FogRamp, float2(depth, 0));
         float4 result = lerp(tex2D(_MainTex, input.uv), fogColor, fogColor.a);
 
         return result;
     }
 
         ENDCG
         SubShader
     {
         Pass
         {
             ZTest Always Cull Off ZWrite Off
 
             CGPROGRAM
             #pragma vertex vert
             #pragma fragment frag
 
             ENDCG
         }
     }
     Fallback off
 }