diff --git a/icu4c/source/common/putil.c b/icu4c/source/common/putil.c
index 0d7280a4f4a..96432839b9d 100644
--- a/icu4c/source/common/putil.c
+++ b/icu4c/source/common/putil.c
@@ -741,11 +741,7 @@ U_CAPI const char* U_EXPORT2
 uprv_tzname(int n)
 {
 #ifdef U_WINDOWS
-#if 0
-    char* id = (char*) detectWindowsTimeZone();
-#else
-    char *id = (char *) u_detectWindowsTimeZone();
-#endif
+    const char *id = u_detectWindowsTimeZone();
 
     if (id != NULL) {
         return id;
diff --git a/icu4c/source/common/wintz.c b/icu4c/source/common/wintz.c
index aa6e847e697..f4773ee032a 100644
--- a/icu4c/source/common/wintz.c
+++ b/icu4c/source/common/wintz.c
@@ -378,7 +378,7 @@ static LONG getTZI(const char *winid, TZI *tzi)
 }
 
 U_CAPI void U_EXPORT2
-u_getWindowsTimeZoneInfo(TIME_ZONE_INFORMATION *zoneInfo, const UChar *icuid, int32_t length)
+uprv_getWindowsTimeZoneInfo(TIME_ZONE_INFORMATION *zoneInfo, const UChar *icuid, int32_t length)
 {
     const char *winid;
     TZI tzi;
@@ -454,7 +454,7 @@ u_getWindowsTimeZoneInfo(TIME_ZONE_INFORMATION *zoneInfo, const UChar *icuid, in
  * time zone, translated to an ICU time zone, or NULL upon failure.
  */
 U_CAPI const char* U_EXPORT2
-u_detectWindowsTimeZone() {
+uprv_detectWindowsTimeZone() {
     LONG result;
     HKEY hkey;
     TZI tziKey;
diff --git a/icu4c/source/common/wintz.h b/icu4c/source/common/wintz.h
index 15c3387b1d0..13ecc379531 100644
--- a/icu4c/source/common/wintz.h
+++ b/icu4c/source/common/wintz.h
@@ -27,10 +27,10 @@ typedef struct _TIME_ZONE_INFORMATION TIME_ZONE_INFORMATION;
 U_CDECL_END
 
 U_CAPI void U_EXPORT2
-u_getWindowsTimeZoneInfo(TIME_ZONE_INFORMATION *zoneInfo, const UChar *icuid, int32_t length);
+uprv_getWindowsTimeZoneInfo(TIME_ZONE_INFORMATION *zoneInfo, const UChar *icuid, int32_t length);
 
 U_CAPI const char* U_EXPORT2
-u_detectWindowsTimeZone();
+uprv_detectWindowsTimeZone();
 
 #endif /* #ifdef U_WINDOWS */
 
diff --git a/icu4c/source/i18n/windtfmt.cpp b/icu4c/source/i18n/windtfmt.cpp
index 9fb24549387..6ae50dbbcde 100644
--- a/icu4c/source/i18n/windtfmt.cpp
+++ b/icu4c/source/i18n/windtfmt.cpp
@@ -152,7 +152,7 @@ UnicodeString &Win32DateFormat::format(Calendar &cal, UnicodeString &appendTo, F
         UnicodeString icuid;
 
         tz.getID(icuid);
-        u_getWindowsTimeZoneInfo(&tzi, icuid.getBuffer(), icuid.length());
+        uprv_getWindowsTimeZoneInfo(&tzi, icuid.getBuffer(), icuid.length());
     }
 
     uct = utmscale_fromInt64((int64_t) cal.getTime(status), UDTS_ICU4C_TIME, &status);
@@ -294,7 +294,7 @@ void Win32DateFormat::setTimeZoneInfo(const TimeZone &zone)
         fZoneID = zoneID;
 
         zone.getID(icuid);
-        u_getWindowsTimeZoneInfo(fTZI, icuid.getBuffer(), icuid.length());
+        uprv_getWindowsTimeZoneInfo(fTZI, icuid.getBuffer(), icuid.length());
     }
 }