We initiate a general approach to the relative braid group symmetries on (universal) ıquantum groups, arising from quantum symmetric pairs of arbitrary finite types, and their modules. Our approach is built on new intertwining properties of quasi K-matrices which we develop and braid group symmetries on (Drinfeld double) quantum groups. Explicit formulas for these new symmetries on ıquantum groups are obtained. We establish a number of fundamental properties for these symmetries on ıquantum groups, strikingly parallel to their well-known quantum group counterparts. We apply these symmetries to fully establish rank one factorizations of quasi K-matrices, and this factorization property in turn helps to show that the new symmetries satisfy relative braid relations. Finally, the above approach allows us to construct compatible relative braid group actions on modules over quantum groups for the first time. WEIQIANG WANG AND WEINAN ZHANG 4.1. Rescaled braid group action on U 4.2. Symmetries T ′′ j,+1 , for j ∈ I • 4.3. Characterization of T ′ i,−1 4.4. Quantum symmetric pairs of diagonal type 4.5. Action of T ′ i,−1 on U ı0 U • 4.6. Integrality of T ′ i,−1 4.7. A uniform formula for T ′ i,−1 (B i ) 5. Rank two formulas for T ′ i,−1 (B j ) 5.1. Some commutator relations with Υ 5.2. Motivating examples: types BI, DI, DIII 4 5.3. Formulation for T ′ i,−1 (B j ) 5.4. Proof of Theorem 5.5 5.5. A comparison with earlier results 6. New symmetries T ′′ i,+1 on U ı 6.1. Characterization of T ′′ i,+1 6.2. Action of T ′′ i,+1 on U ı0 U • 6.3. Rank one formula for T ′′ i,+1 (B i ) 6.4. Rank two formulas for T ′′ i,+1 (B j ) 6.5. T ′ i,e and T ′′ i,−e as inverses 7. A basic property of new symmetries 7.1. Rank 2 cases with ℓ • (w • ) = 3 7.2. Rank 2 cases with ℓ • (w • ) = 4 7.3. Rank 2 case with ℓ • (w • ) = 6 7.4. The general identity T w (B i ) = B wi 8. Factorization of quasi K-matrices 8.1. Factorization of Υ 8.2. Reduction to rank 2 8.3. Factorizations in rank 2 9. Relative braid group actions on ıquantum groups 9.1. Braid group relations among T i 9.2. Action of the braid group Br(W • ) ⋊ Br(W • ) on U ı 9.3. Intertwining properties of T ′ i,+1 , T ′′ i,−1 9.4. Braid group action on U ı ς 10. Relative braid group actions on U-modules 10.1. Intertwining relations on U ı ς 10.2. Compatible actions of T ′ i,e , T ′′ i,e on U-modules 10.3. Relative braid relations on U-modules Appendix A. Proofs of Proposition 5.11 and Table 3 A.1. Some preparatory lemmas A.2. Split types of rank 2 A.3. Type AII