How have courts interpreted a waiver agreement where the waiver agreement was ambiguous or ambiguous?

Then followed Hagar v. Elite Ins. Co., supra, 22 Cal.App.3d 505, 99 Cal.Rptr. 423, in which the court recognized that "a cryptic or ambiguous writing may nevertheless be effective between the parties if extrinsic evidence indicates what the parties actually intended by the language which was used ..." in the waiver agreement. (Id. at p. 512, 99 Cal.Rptr. 423.)

In Grimes v. Elite Ins. Co. (1978) 82 Cal.App.3d 130, 146 Cal.Rptr. 808, it was held that despite the insufficiency of the written waiver agreement the insured, who had purchased his policy in 1971, was not entitled to a directed verdict where there was ample extrinsic evidence that the insured had in fact intentionally waived uninsured motorist coverage.