diff --git a/src/Blocks/utils.jl b/src/Blocks/utils.jl
index bda4200d..1baa46ba 100644
--- a/src/Blocks/utils.jl
+++ b/src/Blocks/utils.jl
@@ -10,9 +10,8 @@
             input = true,
             description = "Inner variable in RealInput $name"
         ]
-        u = collect(u)
     end
-    ODESystem(Equation[], t, [u...], []; name = name, guesses = [u => u_start])
+    ODESystem(Equation[], t, [u], []; name = name, guesses = [u => u_start])
 end
 @doc """
     RealInput(;name, u_start)
@@ -31,8 +30,7 @@ Connector with one input signal of type Real.
         input = true,
         description = "Inner variable in RealInputArray $name"
     ]
-    u = collect(u)
-    ODESystem(Equation[], t, [u...], []; name = name, guesses = [u => u_start])
+    ODESystem(Equation[], t, [u], []; name = name, guesses = [u => u_start])
 end
 @doc """
     RealInputArray(;name, nin, u_start)
@@ -59,9 +57,8 @@ Connector with an array of input signals of type Real.
             output = true,
             description = "Inner variable in RealOutput $name"
         ]
-        u = collect(u)
     end
-    ODESystem(Equation[], t, [u...], []; name = name, guesses = [u => u_start])
+    ODESystem(Equation[], t, [u], []; name = name, guesses = [u => u_start])
 end
 @doc """
     RealOutput(;name, u_start)
@@ -80,8 +77,7 @@ Connector with one output signal of type Real.
         output = true,
         description = "Inner variable in RealOutputArray $name"
     ]
-    u = collect(u)
-    ODESystem(Equation[], t, [u...], []; name = name, guesses = [u => u_start])
+    ODESystem(Equation[], t, [u], []; name = name, guesses = [u => u_start])
 end
 @doc """
     RealOutputArray(;name, nout, u_start)
diff --git a/test/Blocks/utils.jl b/test/Blocks/utils.jl
new file mode 100644
index 00000000..68917d65
--- /dev/null
+++ b/test/Blocks/utils.jl
@@ -0,0 +1,16 @@
+using ModelingToolkitStandardLibrary.Blocks
+using ModelingToolkit
+
+@testset "Guesses" begin
+    for (block, guess) in [
+            (RealInput(; name = :a), 0.0),
+            (RealInput(; nin = 3, name = :a), zeros(3)),
+            (RealOutput(; name = :a), 0.0),
+            (RealOutput(; nout = 3, name = :a), zeros(3)),
+            (RealInputArray(; nin = 3, name = :a), zeros(3)),
+            (RealOutputArray(; nout = 3, name = :a), zeros(3)),
+        ]
+        guesses = ModelingToolkit.guesses(block)
+        @test guesses[@nonamespace block.u] == guess
+    end
+end
diff --git a/test/runtests.jl b/test/runtests.jl
index 35bc5eb4..da9e9a21 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -5,6 +5,9 @@ using SafeTestsets
 end
 
 # Blocks
+@safetestset "Blocks: utils" begin
+    include("Blocks/utils.jl")
+end
 @safetestset "Blocks: math" begin
     include("Blocks/math.jl")
 end