Joint application for an auto loan with differing FICO scores

[Lel]

We're thinking about buying a new car.  We're planning on getting our financing in place before shopping.

I've got a good FICO score - in the upper 700s.  My DW's score was lower by about 50 points the last time we checked, which was a while ago.

DW is a SAHM, so she earns no income.  She wouldn't add anything to application, but I thought it might be nice to give her another TL to help her score.  She doesn't have as many CCs, is not on our HELOC, and on a lot of our "joint" CCs she's actually an AU, not an account owner.

My questions:

1. When determining what rate we would get, would the auto loan folks also use the lower score or lower middle score, just like the mortgage companies?

2. Is having DW as a joint owner/applicant on the account actually going to help her score, in the same way that mortgages have an overall positive effect on scores?  We currently have a car loan (paid off in 2002) still reporting on TU and EQ - but not EX, interestingly.

Thanks! 

[Anonymous]

It depends on the lender.  You should be able to qualify based upon your score and income.  Adding her as co-applicant will help her credit, especially if she is mostly an AU on cards and not much on her own.

[Lel]

I'm pretty confident that I could qualify for the auto loan on my own.  I guess my major question is whether having her on the application, with a lower FICO score, would bar us from getting the most ideal interest rates.  You know, in the same way that when you apply for a mortgage the lenders look at the middle score of the spouse with the lower FICOs.

[Anonymous]

No, not usually.