Conversion Linker Sequencing
You have a Conversion Linker in the container. Good. But it isn't declared as a setup tag for your Google Ads conversion tags. On a fast page load the linker happens to fire first and everything works. On a slow load, a redirect-heavy checkout, or a consent banner mid-page, the order flips. The conversion tag fires before the GCLID has been written to `_gcl_aw`, and that conversion ships without click context. The dashboards still look fine.
Why It Matters
Adding the Conversion Linker tag is necessary. It isn't sufficient. GTM doesn't guarantee any ordering between two tags that share the same trigger. Whichever one finishes its setup first, fires first. That depends on resource loading, consent state, redirects, third-party script injection, and a dozen other things you can't predict from inside Preview mode. Here's the failure mode. The Conversion Linker reads `gclid` from the URL and writes it to a first-party cookie called `_gcl_aw`. The Google Ads conversion tag, when it fires, reads `_gcl_aw` and sends whatever it finds along with the conversion request. If the conversion tag wins the race, `_gcl_aw` is empty, and the conversion is reported without a GCLID. Google still counts it. It just has no idea which campaign drove it. The maddening part is that the failure is intermittent. In Preview mode on a fast dev machine the linker always wins. In production — on a slow connection, behind a privacy proxy, or when the user clicks through a consent banner that triggered a tag reload — the conversion tag occasionally wins. Some users get attribution. Some don't. The dashboard averages out to "mostly working" until somebody runs an audit like this one. GTM has a feature designed exactly for this: Tag Sequencing. You declare that Tag B requires Tag A to fire first, and GTM honors the declaration on every fire regardless of timing. The fix is to mark the Conversion Linker as a setup tag for every Google Ads conversion tag.
How To Fix It
- In GTM, open Workspace → Tags. Pick the first Google Ads Conversion Tracking tag.
- Expand Advanced Settings → Tag Sequencing.
- Tick "Fire a tag before [this tag] fires." Select your Google Ads Conversion Linker as the setup tag.
- Leave "Don't fire [this tag] if [setup tag] fails or is paused" unchecked. If the linker is paused for some reason you usually still want the conversion tag to fire (you just lose the GCLID for that conversion).
- Repeat for every Google Ads Conversion Tracking tag in the container. Yes, all of them. The sequencing has to be declared per-tag.
- In Preview mode, complete a test conversion. Check the Tags Fired panel. The Conversion Linker should appear immediately before each conversion tag, on the same event. Only publish after you have seen the sequencing in Preview. Inferring it from the configuration screen is not enough.
Example
Setup tag: Google Ads Conversion Linker
Conversion tag: Google Ads - Purchase
Tag sequencing: Fire setup tag before Google Ads - Purchase firesThis GTM container has Google Ads conversion tags that share a trigger with the Conversion Linker but do not declare it as a setup tag. Per Google's Tag Sequencing documentation, GTM does not guarantee execution order between tags sharing a trigger; explicit Tag Sequencing is required when one tag depends on the side effects of another. Without it, the conversion tag can fire before the GCLID has been written to `_gcl_aw`, producing intermittent attribution loss that does not show up in dashboards. Fix: configure each Google Ads conversion tag's Tag Sequencing to require the Conversion Linker as a setup tag, and verify in Preview. Source: support.google.com/tagmanager/answer/6238868.
Drop this paragraph into your client deliverable. Sources back to the canonical platform documentation linked below.
References
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