I'm using a zoho form I created to add data into our CRM. Public forms do not allow access to lookup fields (as far as I can tell), so I want to be able to associate it in the CRM with a script.

I'm able to copy a single line field into another single line field without an issue, however I cannot figure out how to copy it into a lookup field (not sure if this is even possible). 

Update_ServicePM = zoho.crm.updateRecord("Inspections", ServicePM_id,{" Actual_Serial_Number": Serial_Form});

ServicePM_id is the id of a record in a custom module

Actual_Serial_Number is the lookup field I want to copy into

Serial_Form is the single line field that comes over when a form is submitted.

Any ideas? Thanks.