diff --git a/server/http_config_helper.go b/server/http_config_helper.go
index 6db0361fe..1d187a1df 100644
--- a/server/http_config_helper.go
+++ b/server/http_config_helper.go
@@ -130,6 +130,11 @@ type testResult = struct {
 	Error string `json:"error"`
 }
 
+func hasFeature(instance any, f api.Feature) bool {
+	fd, ok := instance.(api.FeatureDescriber)
+	return ok && slices.Contains(fd.Features(), f)
+}
+
 // testInstance tests the given instance similar to dump
 // TODO refactor together with dump
 func testInstance(instance any) map[string]testResult {
@@ -159,7 +164,7 @@ func testInstance(instance any) map[string]testResult {
 	if dev, ok := instance.(api.Battery); ok {
 		val, err := dev.Soc()
 		key := "soc"
-		if fd, ok := instance.(api.FeatureDescriber); ok && slices.Contains(fd.Features(), api.Heating) {
+		if hasFeature(instance, api.Heating) {
 			key = "temp"
 		}
 		makeResult(key, val, err)
@@ -225,7 +230,7 @@ func testInstance(instance any) map[string]testResult {
 	if dev, ok := instance.(api.SocLimiter); ok {
 		val, err := dev.GetLimitSoc()
 		key := "vehicleLimitSoc"
-		if fd, ok := instance.(api.FeatureDescriber); ok && slices.Contains(fd.Features(), api.Heating) {
+		if hasFeature(instance, api.Heating) {
 			key = "heaterTempLimit"
 		}
 		makeResult(key, val, err)