diff --git a/browser/experiments/Experiments.jsm b/browser/experiments/Experiments.jsm
index 56f43fbd4433..84e6359a5024 100644
--- a/browser/experiments/Experiments.jsm
+++ b/browser/experiments/Experiments.jsm
@@ -594,7 +594,7 @@ Experiments.Experiments.prototype = {
   }),
 
   _telemetryStatusChanged() {
-    this._toggleExperimentsEnabled(gExperimentsEnabled);
+    this._toggleExperimentsEnabled(gPrefs.get(PREF_ENABLED, false));
   },
 
   /**
diff --git a/browser/experiments/ExperimentsService.js b/browser/experiments/ExperimentsService.js
index da230879e956..d33a70aaf860 100644
--- a/browser/experiments/ExperimentsService.js
+++ b/browser/experiments/ExperimentsService.js
@@ -16,30 +16,19 @@ XPCOMUtils.defineLazyModuleGetter(this, "OS",
                                   "resource://gre/modules/osfile.jsm");
 XPCOMUtils.defineLazyModuleGetter(this, "CommonUtils",
                                   "resource://services-common/utils.js");
+XPCOMUtils.defineLazyModuleGetter(this, "TelemetryUtils",
+                                  "resource://gre/modules/TelemetryUtils.jsm");
+
 
 const PREF_EXPERIMENTS_ENABLED  = "experiments.enabled";
 const PREF_ACTIVE_EXPERIMENT    = "experiments.activeExperiment"; // whether we have an active experiment
-const PREF_TELEMETRY_ENABLED    = "toolkit.telemetry.enabled";
-const PREF_TELEMETRY_UNIFIED    = "toolkit.telemetry.unified";
 const DELAY_INIT_MS             = 30 * 1000;
 
-// Whether the FHR/Telemetry unification features are enabled.
-// Changing this pref requires a restart.
-const IS_UNIFIED_TELEMETRY = Preferences.get(PREF_TELEMETRY_UNIFIED, false);
-
 XPCOMUtils.defineLazyGetter(
   this, "gPrefs", () => {
     return new Preferences();
   });
 
-XPCOMUtils.defineLazyGetter(
-  this, "gExperimentsEnabled", () => {
-    // We can enable experiments if either unified Telemetry or FHR is on, and the user
-    // has opted into Telemetry.
-    return gPrefs.get(PREF_EXPERIMENTS_ENABLED, false) &&
-           IS_UNIFIED_TELEMETRY && gPrefs.get(PREF_TELEMETRY_ENABLED, false);
-  });
-
 XPCOMUtils.defineLazyGetter(
   this, "gActiveExperiment", () => {
     return gPrefs.get(PREF_ACTIVE_EXPERIMENT);
@@ -54,8 +43,15 @@ ExperimentsService.prototype = {
   classID: Components.ID("{f7800463-3b97-47f9-9341-b7617e6d8d49}"),
   QueryInterface: XPCOMUtils.generateQI([Ci.nsITimerCallback, Ci.nsIObserver]),
 
+  get _experimentsEnabled() {
+    // We can enable experiments if either unified Telemetry or FHR is on, and the user
+    // has opted into Telemetry.
+    return gPrefs.get(PREF_EXPERIMENTS_ENABLED, false) &&
+           TelemetryUtils.isTelemetryEnabled;
+  },
+
   notify(timer) {
-    if (!gExperimentsEnabled) {
+    if (!this._experimentsEnabled) {
       return;
     }
     if (OS.Constants.Path.profileDir === undefined) {
@@ -63,7 +59,11 @@ ExperimentsService.prototype = {
     }
     let instance = Experiments.instance();
     if (instance.isReady) {
-      instance.updateManifest();
+      instance.updateManifest().catch(error => {
+        // Don't throw, as this breaks tests. In any case the best we can do here
+        // is to log the failure.
+        Cu.reportError(error);
+      });
     }
   },
 
@@ -77,7 +77,7 @@ ExperimentsService.prototype = {
   observe(subject, topic, data) {
     switch (topic) {
       case "profile-after-change":
-        if (gExperimentsEnabled) {
+        if (this._experimentsEnabled) {
           Services.obs.addObserver(this, "quit-application");
           Services.obs.addObserver(this, "sessionstore-state-finalized");
           Services.obs.addObserver(this, "EM-loaded");
diff --git a/browser/experiments/test/xpcshell/test_telemetry_disabled.js b/browser/experiments/test/xpcshell/test_telemetry_disabled.js
index 74f85ccfc7e8..7ef5f87cead9 100644
--- a/browser/experiments/test/xpcshell/test_telemetry_disabled.js
+++ b/browser/experiments/test/xpcshell/test_telemetry_disabled.js
@@ -13,9 +13,16 @@ add_test(function test_experiments_activation() {
   Services.prefs.setBoolPref(PREF_TELEMETRY_ENABLED, false);
 
   let experiments = Experiments.instance();
+
   Assert.ok(!experiments.enabled, "Experiments must be disabled if Telemetry is disabled.");
 
-  // TODO: Test that Experiments are turned back on when bug 1232648 lands.
+  // Patch updateManifest to not do anything when the pref is switched back to true,
+  // otherwise it attempts to connect to the server.
+  experiments.updateManifest = () => Promise.resolve();
+
+  Services.prefs.setBoolPref(PREF_TELEMETRY_ENABLED, true);
+
+  Assert.ok(experiments.enabled, "Experiments must be re-enabled if Telemetry is re-enabled");
 
   run_next_test();
 });
diff --git a/toolkit/components/telemetry/tests/unit/head.js b/toolkit/components/telemetry/tests/unit/head.js
index 544d39885078..402d147fe2b9 100644
--- a/toolkit/components/telemetry/tests/unit/head.js
+++ b/toolkit/components/telemetry/tests/unit/head.js
@@ -311,6 +311,9 @@ if (runningInParent) {
   // if receive an unexpected ping. Let's globally disable the shutdown ping sender:
   // the relevant tests will enable this pref when needed.
   Services.prefs.setBoolPref("toolkit.telemetry.shutdownPingSender.enabled", false);
+  // Ensure browser experiments are also disabled, to avoid network activity
+  // when toggling PREF_ENABLED.
+  Services.prefs.setBoolPref("experiments.enabled", false);
 
 
   fakePingSendTimer((callback, timeout) => {